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Clinical features and disease progression of L-2-hydroxyglutaric aciduria in 27 Staffordshire bull terriers
Abstract
To describe the development of clinical signs (CS) and outcome of L-2-hydroxyglutaric aciduria (L-2-HGA), owners of 119 Staffordshire bull terriers positive for the known L-2-hydroxyglutarate dehydrogenase autosomal-recessive mutations were requested to complete a questionnaire regarding their pet's CS. Questionnaires were returned for 27 dogs, all with neurological abnormalities—not all questions were answered in all cases. The mean age of CS onset was 12 months (range 2.5–60). Gait dysfunction was reported in 26/26 dogs, with stiffness of all four limbs the most common (24/26) and earliest recognised abnormality. Kyphosis (19/26), body and/or head tremors (19/26) and hypermetria (15/26) were frequent. Behavioural changes were present in 24/27 dogs; most commonly staring into space (21/24), signs of dementia (17/24) and loss of training (15/24). Eighteen dogs demonstrated paroxysmal seizure-like/dyskinetic episodes. Nineteen (70 per cent) dogs were alive at a mean survival time of 76.6 months (12–170) after onset of CS. L-2-HGA was the cause of euthanasia in six dogs. Euthanasia occurred at a mean survival time of 44 months (8.5–93) after onset of CS, with 2/8 dogs euthanased within 12 months. L-2-HGA is considered a progressive neurological disease; however, CS can be successfully managed with affected dogs potentially living a normal lifespan.
... [1][2][3][4][5] The clinical signs and magnetic resonance imaging (MRI) findings in dogs and cats with L2HGA have been reported previously. [3][4][5][6][7][8][9][10] Our purpose was to describe a novel candidate disease-causing variant for L2HGA in a cat with previously unreported MRI findings and a fatal outcome. ...
... 1,2 In Staffordshire bull terriers, the most common clinical signs include gait abnormalities and behavioral changes, with seizurelike episodes observed in two-thirds of the cases. 9 In the other dog breeds only small number of cases have been reported: the West Highland white terrier presented with gait abnormalities, impaired vision, behavioral changes and episodic head tremors, but no seizurelike episodes; and 2 of the previously reported Yorkshire terriers presented with generalized tonic-clonic seizures. [8][9][10] Characteristic MRI changes have been reported previously in dogs and humans with L2HGA. ...
... 9 In the other dog breeds only small number of cases have been reported: the West Highland white terrier presented with gait abnormalities, impaired vision, behavioral changes and episodic head tremors, but no seizurelike episodes; and 2 of the previously reported Yorkshire terriers presented with generalized tonic-clonic seizures. [8][9][10] Characteristic MRI changes have been reported previously in dogs and humans with L2HGA. In humans, the lesions primarily affect the white matter and are in the frontal and subcortical regions, although the dentate nuclei also are commonly affected. ...
Case description:
A 9-month-old intact male domestic shorthair cat was evaluated for increasing frequency of generalized tonic-clonic seizures.
Clinical findings:
The cat was reported to have had episodes of circling between the seizures. Upon examination, the cat had bilateral inconsistent menace response but otherwise normal physical and neurological examinations.
Diagnostics:
Magnetic resonance imaging (MRI) of the brain identified multifocal, small, rounded intra-axial lesions within the subcortical white matter containing fluid with similar characteristics as cerebrospinal fluid. Evaluation of urine organic acids showed increased excretion of 2-hydroxyglutaric acid. An XM_023255678.2:c.397C>T nonsense variant in the L2HGDH gene encoding L-2-hydroxyglutarate dehydrogenase was identified using whole genome sequencing.
Treatment and outcome:
Levetiracetam treatment was initiated at 20 mg/kg PO q8h, but the cat died after a seizure 10 days later.
Clinical relevance:
We report the second pathogenic gene variant in L-2-hydroxyglutaric aciduria in cats and describe for the first time multicystic cerebral lesions on MRI.
... As clinical, radiological and biochemical findings resembled previously published cases of companion animals with L-2-HGA [4,6], we hypothesized that the phenotype in the affected cat was due to a variant in the L2HGDH gene. Hence, L2HGDH was investigated as the top functional candidate gene. ...
... In the previous case [5], generalized tonic-clonic epileptic seizures were reported, while our case displayed multiple episodes of running frantically around the house, often in circles, for approximately 30-60 s, bumping into obstacles, having altered mentation and autonomic signs, including salivation and often urination. These episodes are similar to those described in some dogs with L-2-HGA [6]. Despite the lack of a specific treatment for this neurometabolic disease, anti-epileptic medication seems to improve the frequency of the epileptic seizure activity. ...
... Variants in human and canine L2HGDH cause L-2-HGA [6,9]. Interestingly, the variant described herein constitutes an amino acid change at the same position as one of the two amino acid changes discovered in Staffordshire Bull Terriers by Penderis et al. (XP_038529514.1:Leu433Pro, ...
A 7-month-old, spayed female, domestic longhair cat with L-2-hydroxyglutaric aciduria (L-2-HGA) was investigated. The aim of this study was to investigate the clinical signs, metabolic changes and underlying genetic defect. The owner of the cat reported a 4-month history of multiple paroxysmal seizure-like episodes, characterized by running around the house, often in circles, with abnormal behavior, bumping into obstacles, salivating and often urinating. The episodes were followed by a period of disorientation and inappetence. Neurological examination revealed an absent bilateral menace response. Routine blood work revealed mild microcytic anemia but biochemistry, ammonia, lactate and pre- and post-prandial bile acids were unremarkable. MRI of the brain identified multifocal, bilaterally symmetrical and T2-weighted hyperintensities within the prosencephalon, mesencephalon and metencephalon, primarily affecting the grey matter. Urinary organic acids identified highly increased levels of L-2-hydroxyglutaric acid. The cat was treated with the anticonvulsants levetiracetam and phenobarbitone and has been seizure-free for 16 months. We sequenced the genome of the affected cat and compared the data to 48 control genomes. L2HGDH, coding for L-2-hydroxyglutarate dehydrogenase, was investigated as the top functional candidate gene. This search revealed a single private protein-changing variant in the affected cat. The identified homozygous variant, XM_023255678.1:c.1301A>G, is predicted to result in an amino acid change in the L2HGDH protein, XP_023111446.1:p.His434Arg. The available clinical and biochemical data together with current knowledge about L2HGDH variants and their functional impact in humans and dogs allow us to classify the p.His434Arg variant as a causative variant for the observed neurological signs in this cat.
... Although, to our knowledge, there is no reported presentation in cats, the condition is well described in dogs with gait dysfunction, body and/or head tremors and seizure-like/dyskinetic episodes reported in Staffordshire Bull Terriers. 3 There are two chiral forms: L-2-HGA and D-2-HGA, with a third, mixed form D-, L-2-HGA reported in human medicine. 4 L-2-HGA has been described in Staffordshire Bull Terriers, 2,3 a West Highland White Terrier 5 and Yorkshire Terriers. ...
... 14 The age of the cat (14 months) fits with the pattern seen in the Staffordshire Bull Terrier, with a mean age of onset of clinical signs reported at 12 months of age. 3 Interestingly, the clinical signs manifesting in this case were generalised tonicclonic seizures; however, the cerebral cortex appears to be unaffected on MRI. Seizures or seizure-like episodes are reported in both dogs 2,3 and people, 4 although there is some variation in these episodes, with dyskinesias appearing to be more common in dogs. ...
... The course of this disease seems relatively slowly progressive/static in nature, owing to the fact the cat is still alive 12 months after diagnosis, with episodes occurring every 2-3 months, with the same slow progression reported in Staffordshire Bull Terriers. 3 The response to phenobarbitone in this cat would represent a complete treatment success based on the International Veterinary Epilepsy Task Force guidelines. 19 There was a greater than three-fold increase in the post-treatment interictal period (60 days) vs the longest pretreatment interictal period (9 days). ...
Case summary:
A 14-month-old male castrated domestic shorthair cat, which 2 months prior to presentation underwent hindlimb amputation following a road traffic accident, presented for investigation of four suspected generalised tonic-clonic seizures. Neurological examination was unremarkable. Routine blood work (haematology, biochemistry, ammonia, preprandial bile acids) was unremarkable. MRI of the brain identified marked symmetrical T2-weighted hyperintensities of the cerebellum and brainstem, mainly affecting the grey matter. Urine amino acid and mucopolysaccharide levels were unremarkable. Urine organic acids on two separate samples, 35 days apart, identified highly increased excretion of 2-hydroxyglutaric acid, indicative of 2-hydroxyglutaric aciduria. The cat was started on anticonvulsant therapy with phenobarbitone, which, at the point of writing, has improved seizure control, although the cat has not achieved seizure freedom.
Relevance and novel information:
This case report describes the first reported case of a 2-hydroxyglutaric aciduria, an inherited neurometabolic disorder, as a cause for seizure-like episodes in a cat.
... The affected parenchyma is mildly hypointense on T1W images. [1][2][3] There is usually no abnormal contrast medium enhancement or mass effect, 1-3 but gray matter swelling has been described. 2 Correlation between the extent of brain lesions on MRI and clinical signs in humans has not been reliably reported. ...
Inborn errors of metabolism are genetic disorders caused by a block in a metabolic pathway, affecting both humans and animals. Individually, they are rare diseases, but as a group they are relatively common. As most of them have recessive inheritance, a new case may seem like just a sporadic case. The high degree of inbreeding in dog breeds increases the frequency of heterozygotes in populations, maintaining mutations (variants) in healthy individuals and, consequently, increasing the risk of disease recurrence (homozygotes). General practitioners' familiarization with this subject is a significant factor in identifying new cases, contributing to increased knowledge about inborn errors of metabolism and their control. To help general practitioners, we use a clinical genetics approach covering key genetic, metabolic, diagnostic, and therapeutic aspects, offering an overview that integrates knowledge about these diseases in dogs and humans.
A variety of systemic disease and toxicities may affect the heart, resulting in arrhythmias. Additionally, some non‐cardiac conditions can result in signs such as collapse. This chapter presents arrhythmias secondary to autonomic disturbance, hypoxia, electrolyte and acid–base disturbances, endocrinopathies, abdominal disease, trauma, drugs and intoxications and also selected non‐cardiac causes of collapse and episodic weakness.
L-2-HYDROXYGLUTARIC aciduria (L-2-HGA) is an autosomal recessive inborn error of metabolism. Most inborn errors of metabolism are rare, require specialised testing for diagnosis and are rapidly fatal (Sewell and others 2007), which means they are not particularly relevant to a general practitioner. However, general practitioners should have a good working knowledge of L-2-HGA for three reasons.
First, this is not a particularly rare condition; approximately 10 per cent of Staffordshire bull terriers (SBTs) in the UK and Finland carry at least one defective copy of the L-2-hydroxyglutarate dehydrogenase gene (L-2- HGDH) (Short and others 2010), that is, are heterozygotes. In a paper summarised on p 545 in this issue of Veterinary Record , Shea and others (2016) report that at least 122 SBTs with L-2-HGA (ie, homozygous recessive dogs) were identified in the UK between 2005 and 2015. That is 12 dogs a year. As a comparison, 30 to 40 vaccine-associated sarcoma were reported to the Veterinary Medicine's Directorate annually between 2003 and 2006 and, most vets are aware of this. Affected dogs typically only manifest signs severe enough to prompt presentation to a vet when the dog is in adulthood. This enzymopathy is rarely fatal, so affected dogs will visit their vet many times for routine care. Therefore many vets in general practice in the UK at some point may be presented with a …
Patients with L-2-hydroxyglutaric aciduria are at risk for developing cerebral neoplasms, particularly gliomas, as one of the optical isomers of the known oncometabolite, 2-hydroxyglutarate is produced in L-2-hydroxyglutaric aciduria. To illustrate the concept of sustained oncogenic potential in permanent exposure to L-2-hydroxyglutarate in brain tissue, we present the medical history of a patient with L-2-hydroxyglutaric aciduria who underwent surgery to remove a right temporal anaplastic astrocytoma and developed an anatomically distinct, but histopathologically similar, tumor in the left frontal region 40 months later. This is the first reported case of successive distinct gliomas in a patient with L-2-hydroxyglutaric aciduria. While this implies a significant, cumulative lifetime risk for cerebral neoplasms in patients with this rare organic aciduria, it also allows further insight into a unique mechanism of tumorigenesis in the brain.
L-2 hydroxyglutaric aciduria is an autosomal recessive error of metabolism that manifests as an encephalopathy. The most common presenting signs are seizures, tremors, ataxia and/ or dementia. Some affected dogs show only subtle behavioural changes. Amongst canines, the condition has been best described in Staffordshire Bull Terriers. Although this is the first reported case in South Africa, at least three other affected dogs have been indentified by polmerase chain reaction (PCR) in this country. Affected dogs have normal haematology, serum biochemistry and routine urine analysis. This report discusses the advantages and limitations of the three main diagnostic modalities, namely: magnetic resonance imaging, urine gas chromatography-mass spectrometry and genetic testing. The aim of this report is to increase awareness of the condition, assist diagnosis in encephalopathic dogs and improve detection of carriers amongst breeding stock.
Two female Yorkshire terrier puppies were presented with generalized tonic-clonic seizures and ataxia. MRI revealed bilaterally symmetrical, diffuse regions of gray matter hyperintensity on T2-weighted and fluid-attenuated inversion recovery sequences. Urinary organic acids were quantified by gas chromatography-mass spectroscopy and were consistent with a diagnosis of L-2-hydroxyglutaric aciduria (L2HGA). The L2HGDH gene encodes for the enzyme L-2-hydroxyglutarate dehydrogenase, which helps break down L-2-hydroxyglutaric acid. In both puppies described in this report, a homozygous mutation at the translation initiation codon of the homolog canine L2HGDH gene was detected (c.1A>G; p.Met1?), confirming the diagnosis of L2HGA at the DNA level. Canine L2HGA is caused by more than one mutation of L2HGDH, as reported in humans.
L-2-hydroxyglutaric aciduria is a metabolic repair deficiency characterized by elevated levels of L-2-hydroxyglutaric acid in urine, blood and cerebrospinal fluid. Neurological signs associated with the disease in humans and dogs include seizures, ataxia and dementia.
Here we describe an 8 month old Yorkshire terrier that presented with episodes of hyperactivity and aggressive behavior. Between episodes, the dog's behavior and neurologic examinations were normal. A T2 weighted MRI of the brain showed diffuse grey matter hyperintensity and a urine metabolite screen showed elevated 2-hydroxyglutaric acid. We sequenced all 10 exons and intron-exon borders of L2HGDH from the affected dog and identified a homozygous A to G transition in the initiator methionine codon. The first inframe methionine is at p.M183 which is past the mitochondrial targeting domain of the protein. Initiation of translation at p.M183 would encode an N-terminal truncated protein unlikely to be functional.
We have identified a mutation in the initiation codon of L2HGDH that is likely to result in a non-functional gene. The Yorkshire terrier could serve as an animal model to understand the pathogenesis of L-2-hydroxyglutaric aciduria and to evaluate potential therapies.
The organic acidurias D: -2-hydroxyglutaric aciduria (D-2-HGA), L-2-hydroxyglutaric aciduria (L-2-HGA), and combined D,L-2-hydroxyglutaric aciduria (D,L-2-HGA) cause neurological impairment at young age. Accumulation of D-2-hydroxyglutarate (D-2-HG) and/or L-2-hydroxyglutarate (L-2-HG) in body fluids are the biochemical hallmarks of these disorders. The current review describes the knowledge gathered on 2-hydroxyglutaric acidurias (2-HGA), since the description of the first patients in 1980. We report on the clinical, genetic, enzymatic and metabolic characterization of D-2-HGA type I, D-2-HGA type II, L-2-HGA and D,L-2-HGA, whereas for D-2-HGA type I and type II novel clinical information is presented which was derived from questionnaires.
Increasing evidence suggests that patients with L2-HGA have a predisposition to cerebral neoplasms. This may be related to the pathologic accumulation of L2-HG because high amounts of 2-HG have been found in brain neoplasms that have IDH1 mutations. Our experience, on the basis of 11 previously unreported cases of L2-HGA, 3 of which developed cerebral neoplasms during the course of the disease, also supports an association between L2-HGA and cerebral neoplasms. We conducted a meta-analysis of published data, and we identified 295 patients (including our 11 patients) with L2-HGA. In 14 patients, the metabolic disorder was associated with cerebral neoplasms, suggesting an approximately 5% prevalence rate of CNS neoplasms in patients with L2-HGA; nonetheless, it may still be an underestimate. L2-HGA is an important disease "model" that provides further evidence to support the recently proposed pathogenetic role of 2-HG in the development of cerebral neoplasms.
Hypomyelination is observed in the context of a growing number of genetic disorders that share clinical characteristics. The aim of this study was to determine the possible role of magnetic resonance imaging pattern recognition in distinguishing different hypomyelinating disorders, which would facilitate the diagnostic process. Only patients with hypomyelination of known cause were included in this retrospective study. A total of 112 patients with Pelizaeus-Merzbacher disease, hypomyelination with congenital cataract, hypomyelination with hypogonadotropic hypogonadism and hypodontia, Pelizaeus-Merzbacher-like disease, infantile GM1 and GM2 gangliosidosis, Salla disease and fucosidosis were included. The brain scans were rated using a standard scoring list; the raters were blinded to the diagnoses. Grouping of the patients was based on cluster analysis. Ten clusters of patients with similar magnetic resonance imaging abnormalities were identified. The most important discriminating items were early cerebellar atrophy, homogeneity of the white matter signal on T(2)-weighted images, abnormal signal intensity of the basal ganglia, signal abnormalities in the pons and additional T(2) lesions in the deep white matter. Eight clusters each represented mainly a single disorder (i.e. Pelizaeus-Merzbacher disease, hypomyelination with congenital cataract, hypomyelination with hypogonadotropic hypogonadism and hypodontia, infantile GM1 and GM2 gangliosidosis, Pelizaeus-Merzbacher-like disease and fucosidosis); only two clusters contained multiple diseases. Pelizaeus-Merzbacher-like disease was divided between two clusters and Salla disease did not cluster at all. This study shows that it is possible to separate patients with hypomyelination disorders of known cause in clusters based on magnetic resonance imaging abnormalities alone. In most cases of Pelizaeus-Merzbacher disease, hypomyelination with congenital cataract, hypomyelination with hypogonadotropic hypogonadism and hypodontia, Pelizaeus-Merzbacher-like disease, infantile GM1 and GM2 gangliosidosis and fucosidosis, the imaging pattern gives clues for the diagnosis.
Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2), are present in most gliomas and secondary glioblastomas, but are rare in other neoplasms. IDH1/2 mutations are heterozygous, and affect a single arginine residue. Recently, IDH1 mutations were identified in 8% of acute myelogenous leukemia (AML) patients. A glioma study revealed that IDH1 mutations cause a gain-of-function, resulting in the production and accumulation of 2-hydroxyglutarate (2-HG). Genotyping of 145 AML biopsies identified 11 IDH1 R132 mutant samples. Liquid chromatography-mass spectrometry metabolite screening revealed increased 2-HG levels in IDH1 R132 mutant cells and sera, and uncovered two IDH2 R172K mutations. IDH1/2 mutations were associated with normal karyotypes. Recombinant IDH1 R132C and IDH2 R172K proteins catalyze the novel nicotinamide adenine dinucleotide phosphate (NADPH)-dependent reduction of alpha-ketoglutarate (alpha-KG) to 2-HG. The IDH1 R132C mutation commonly found in AML reduces the affinity for isocitrate, and increases the affinity for NADPH and alpha-KG. This prevents the oxidative decarboxylation of isocitrate to alpha-KG, and facilitates the conversion of alpha-KG to 2-HG. IDH1/2 mutations confer an enzymatic gain of function that dramatically increases 2-HG in AML. This provides an explanation for the heterozygous acquisition of these mutations during tumorigenesis. 2-HG is a tractable metabolic biomarker of mutant IDH1/2 enzyme activity.
We report a male infant with L-2-hydroxyglutaric aciduria and Wilms tumor. L-2-hydroxyglutaric aciduria is a rare, autosomal-recessive, inborn error of metabolism characterized by a variable degree of progressive encephalopathy. Of the fewer than 100 cases reported in the literature, at least 9 patients have developed tumors of the central nervous system. To our knowledge, the present case is the 1st example of an extracranial tumor associated with L-2-hydroxyglutaric aciduria. This observation potentially widens the tumor spectrum in this metabolic disorder and may lead to further insight into the relationship between L-2-hydroxyglutaric acid and cellular transformation.
We present clinical, biochemical and cranial magnetic resonance imaging data of six pediatric patients with L-2-hydroxyglutaric aciduria. All the children have the same ethic origin and lived in the northern area of Portugal. Our findings reinforce the described phenotype of this rare metabolic disease with mental deficiency, severe cerebellar dysfunction, mild extrapyramidal and pyramidal symptoms, progressive macrocephaly and seizures. Magnetic resonance imaging revealed subcortical leukoencephalopathy, cerebellar atrophy and signal changes in the putamina and dentate nuclei. These were similar to those of the previous reports in all patients. The urinary excretion of L-2-hydroxyglutaric acid was variably increased in all patients. The other persistent biochemical abnormality was hyperlysinemia. We have found a strong correlation between the severity of the clinical manifestations and the extension of the lesions in the neuroimaging studies. There was no correlation between the clinical findings and the amount of urinary excretion of L-2-hydroxyglutaric acid. We report the second case in the literature of a cerebral thalamic tumor in L-2-hydroxyglutaric aciduria; neuropathological examination of the surgical biopsy demonstrated a diffuse fibrillary astrocytoma.
L-2-Hydroxyglutaric aciduria is an inborn error of metabolism, which has been recognized in humans since 1980. The metabolic defect responsible for the disease is unknown, but the disorder can be diagnosed in humans by elevations of the organic acid, L-2-hydroxyglutaric acid in the cerebrospinal fluid (CSF), plasma, and urine of affected patients. The disorder produces a variety of clinical neurological defects in humans including psychomotor retardation, seizures, and ataxia. There have previously been no recognized animal models of the disease. However, 6 Staffordshire Bull Terriers were recently identified with the disorder. The animals presented with a variety of clinical signs, most notably seizures, ataxia, dementia, and tremors. They were all screened for organic acid abnormalities in urine, and CSF and plasma (when available). Levels of L-2-hydroxyglutaric acid were elevated in all body fluids evaluated. The clinical, clinicopathologic, and magnetic resonance imaging (MRI) characteristics associated with L-2-hydroxyglutaric acid in Stafforshire Bull Terriers is reported herein and represents the first veterinary model of this inborn error of metabolism.
l-2-hydroxyglutaric aciduria (l-2-HGA) is a neurometabolic disorder that produces a variety of clinical neurological deficits, including psychomotor retardation, seizures and ataxia. The biochemical hallmark of l-2-HGA is the accumulation of l-2-hydroxyglutaric acid (l-2-HG) in cerebrospinal fluid, plasma and urine. Mutations within the gene L2HGDH (Entrez Gene ID 79944) on chromosome 14q22 encoding L-2-hydroxyglutaric acid dehydrogenase have recently been shown to cause l-2-HGA in humans. Using a candidate gene approach in an outbred pet dog population segregating l-2-HGA, the causal molecular defect was identified in the canine homologue of L2HGDH and characterised. DNA sequencing and pedigree analysis indicate a common founder effect in the canine model. The canine model shares many of the clinical and MRI features of the disease in humans and represents a valuable resource as a spontaneous model of l-2-HGA.
Patients affected by L-2-hydroxyglutaric aciduria (L-2-HGA) are biochemically characterized by elevated L-2-hydroxyglutaric acid (L-2-HG) concentrations in cerebrospinal fluid, plasma and urine due to a blockage in the conversion of L-2-HG to α-ketoglutaric acid. Neurological symptoms associated with basal ganglia and cerebelar abnormalities whose pathophysiology is still unknown are typical of this neurometabolic disorder. In the present study we evaluated the early effects (30min after injection) of an acute in vivo intrastriatal and intracerebellar L-2-HG administration on redox homeostasis in rat striatum and cerebellum, respectively. Histological analysis of these brain structures were also carried out 7 days after L-2-HG treatment (long-term effects). L-2-HG significant decreased the concentrations of reduced (GSH) and total glutathione (tGS), as well as of glutathione peroxidase (GPx) and reductase (GR) activities, but did not change the activities of superoxide dismutase and catalase in striatum. Furthermore, the concentrations of oxidized glutathione (GSSG) and malondialdehyde (MDA), as well as 2',7'-dichlorofluorescein (DCFH) oxidation and hydrogen peroxide (H2O2) production were increased, whereas carbonyl formation and nitrate plus nitrite concentrations were not altered by L-2-HG injection. It was also found that the melatonin, ascorbic acid plus α-tocopherol and creatine totally prevented most of these effects, whereas N-acetylcysteine, the non competitive glutamate NMDA antagonist MK-801 and the nitric oxide synthase inhibitor L-NAME were not able to normalize the redox alterations elicited by L-2-HG in striatum. L-2-HG intracerebellar injection similarly provoked a decrease of antioxidant defenses (GSH, tGS, GPx and GR) and an increase of the concentrations of GSSG, MDA and H2O2 in cerebellum. These results strongly indicate that the major accumulating metabolite in L-2-HGA induce oxidative stress by decreasing the antioxidant defenses and enhancing reactive oxygen species in striatum and cerebellum of adolescent rats. Regarding to the histopathological findings, L-2-HG caused intense vacuolation, lymphocyte and macrophage infiltrates, eosinofilic granullar bodies and necrosis in striatum. Immunohistochemistry revealed that L-2-HG treatment provoked an increase of GFAP and a decrease of NeuN immunostaining, indicating reactive astroglyosis and reduction of neuronal population, respectively, in striatum. Similar macrophage infiltrates, associated with less intense vacuolation and lymphocytic infiltration were observed in cerebellum. However, we did not observe necrosis, eosinofilic granullar bodies and alteration of GFAP and NeuN content in L-2-HG-teated cerebellum. Taken together the biochemical and histological findings, it is presumed that L-2-HG provokes striatal and cerebellar damage in vivo possibly through oxidative stress induction. Therefore, we postulate that antioxidants may serve as adjuvant therapy allied to the current treatment based on a protein restricted diet and riboflavin and L-carnitine supplementation in patients affected by L-2-HGA.
Copyright © 2015. Published by Elsevier Inc.
Improved understanding of longevity represents a significant welfare opportunity for the domestic dog, given its unparalleled morphological diversity. Epidemiological research using electronic patient records (EPRs) collected from primary veterinary practices overcomes many inherent limitations of referral clinic, owner questionnaire and pet insurance data. Clinical health data from 102,609 owned dogs attending first opinion veterinary practices (n=86) in central and southeast England were analysed, focusing on 5095 confirmed deaths. Of deceased dogs with information available, 3961 (77.9%) were purebred, 2386 (47.0%) were female, 2528 (49.8%) were neutered and 1105 (21.7%) were insured. The overall median longevity was 12.0years (IQR 8.9-14.2). The longest-lived breeds were the Miniature poodle, Bearded collie, Border collie and Miniature dachshund, while the shortest-lived were the Dogue de Bordeaux and Great Dane. The most frequently attributed causes of death were neoplastic, musculoskeletal and neurological disorders. The results of multivariable modelling indicated that longevity in crossbred dogs exceeded purebred dogs by 1.2years (95% confidence interval 0.9-1.4; P<0.001) and that increasing bodyweight was negatively correlated with longevity. The current findings highlight major breed differences for longevity and support the concept of hybrid vigour in dogs.
Prevalence is the best indicator of cancer survivorship in the population, but few studies have focused on brain tumor prevalence because of previous data limitations. Hence, the full impact of primary brain tumors on the healthcare system in the United States is not completely described. The present study provides an estimate of the prevalence of disease in the United States, updating an earlier prevalence study. Incidence data for 2004 and survival data for 1985-2005 were obtained by the Central Brain Tumor Registry of the United States from selected regions, modeled under 2 different survival assumptions, to estimate prevalence rates for the year 2004 and projected estimates for 2010. The overall incidence rate for primary brain tumors was 18.1 per 100 000 person-years with 2-, 5-, 10-, and 20-year observed survival rates of 62%, 54%, 45%, and 30%, respectively. On the basis of the sum of nonmalignant and averaged malignant estimates, the overall prevalence rate of individuals with a brain tumor was estimated to be 209.0 per 100 000 in 2004 and 221.8 per 100 000 in 2010. The female prevalence rate (264.8 per 100 000) was higher than that in males (158.7 per 100 000). The averaged prevalence rate for malignant tumors (42.5 per 100 000) was lower than the prevalence for nonmalignant tumors (166.5 per 100 000). This study provides estimates of the 2004 (n = 612 770) and 2010 (n = 688 096) expected number of individuals living with primary brain tumor diagnoses in the United States, providing more current and robust estimates for aiding healthcare planning and patient advocacy for an aging US population.
L-2-Hydroxyglutaric aciduria (L2HGA) is a rare, neurometabolic disorder with an autosomal recessive mode of inheritance. Affected individuals only have neurological manifestations, including psychomotor retardation, cerebellar ataxia, and more variably macrocephaly, or epilepsy. The diagnosis of L2HGA can be made based on magnetic resonance imaging (MRI), biochemical analysis, and mutational analysis of L2HGDH. About 200 patients with elevated concentrations of 2-hydroxyglutarate (2HG) in the urine were referred for chiral determination of 2HG and L2HGDH mutational analysis. All patients with increased L2HG (n=106; 83 families) were included. Clinical information on 61 patients was obtained via questionnaires. In 82 families the mutations were detected by direct sequence analysis and/or multiplex ligation dependent probe amplification (MLPA), including one case where MLPA was essential to detect the second allele. In another case RT-PCR followed by deep intronic sequencing was needed to detect the mutation. Thirty-five novel mutations as well as 35 reported mutations and 14 nondisease-related variants are reviewed and included in a novel Leiden Open source Variation Database (LOVD) for L2HGDH variants (http://www.LOVD.nl/L2HGDH). Every user can access the database and submit variants/patients. Furthermore, we report on the phenotype, including neurological manifestations and urinary levels of L2HG, and we evaluate the phenotype-genotype relationship.
The neurometabolic disorder L: -2-hydroxyglutaric aciduria is caused by mutations in a gene present on chromosome 14q22.1 and encoding L: -2-hydroxyglutarate dehydrogenase. This FAD-linked mitochondrial enzyme catalyses the irreversible conversion of L: -2-hydroxyglutarate to alpha-ketoglutarate. The formation of L: -2-hydroxyglutarate results from a side-activity of mitochondrial L: -malate dehydrogenase, the enzyme that interconverts oxaloacetate and L: -malate, but which also catalyses, very slowly, the NADH-dependent conversion of alpha-ketoglutarate to L: -2-hydroxyglutarate. L: -2-Hydroxyglutarate has no known physiological function in eukaryotes and most prokaryotes. Its accumulation is toxic to the mammalian brain, causing a leukoencephalopathy and increasing the susceptibility to develop tumours. L: -2-Hydroxyglutaric aciduria appears to be the first disease of 'metabolite repair'.
L -2-Hydroxyglutaric aciduria (L -2-OHGA) is a rare autosomal recessive inherited encephalopathy. This inborn error, characterized by psychomotor retardation, progressive ataxia and typical magnetic resonance imaging findings, presents in early infancy. To make a definitive diagnosis, an anomalous accumulation of L -2-hydroxyglutaric acid must be detected in body fluids. Here, we present a 17-year-old boy with L: -2-OHGA who developed an anaplastic ependymoma during the course of this disease. We also present a literature review including seven other patients who developed malignant brain tumors during the course of L -2-OHGA. This correlation may indicate a possible increased risk of brain tumors among patients with L -2-hydroxyglutaric aciduria.
A 5-year-old boy, excreting large amounts of 2-hydroxyglutaric acid in the urine (3.3-7.6 mmol/l), is described. The patient presented with psychomotor retardation and dystrophy. His skeletal age was delayed. The EEG was not well differentiated; it resembled that observed in 2-year-old children. There was a severe anaemia, which reacted well to iron supplements. The 2-hydroxyglutaric acid was found to have the L-configuration, as analysed by capillary gas chromatography of the O-acetylated di-(-)-2-butyl ester derivative. The relation of L-2-hydroxyglutarate excretion to known metabolic pathways is discussed.
L-2-Hydroxyglutaric aciduria (L-2-HGA) is a rare organic aciduria with a slowly progressive course regarding CNS involvement. We present a 13.5-year-old female patient who presented at the Emergency Department with a generalized status epilepticus, which promptly responded to intravenous phenytoin. CT and MRI demonstrated subcortical white matter alterations. The neurological examination revealed mild mental retardation, macrocephaly and ataxic gait with cerebellar signs. Repeated urinary organic acid analysis demonstrated increased excretion of 2-hydroxyglutaric acid which was of the L-configuration. The constellation of macrocephaly in a patient with mental retardation, cerebellar tract involvement and subcortical white matter signal alterations on MRI should alert the physician to the possibility of L-2-HGA. Although rare, epileptic seizures or even status epilepticus can be among the presenting symptoms in organic acidurias with a slow course, such as L-2-HGA.
L-2-Hydroxyglutaric acid (LGA) is the biochemical hallmark of patients affected by the neurometabolic disorder known as L-2-hydroxyglutaric aciduria (LHGA). Although this disorder is predominantly characterized by severe neurological findings and pronounced cerebellum atrophy, the neurotoxic mechanisms of brain injury are virtually unknown. In the present study, we investigated the effect of LGA, at 0.25-5mM concentrations, on total creatine kinase (tCK) activity from cerebellum, cerebral cortex, cardiac muscle and skeletal muscle homogenates of 30-day-old Wistar rats. CK activity was measured also in the cytosolic (Cy-CK) and mitochondrial (Mi-CK) fractions from cerebellum. We verified that tCK activity was significantly inhibited by LGA in the cerebellum, but not in cerebral cortex, cardiac muscle and skeletal muscle. Furthermore, CK activity from the mitochondrial fraction was inhibited by LGA, whereas that from the cytosolic fraction of cerebellum was not affected by the acid. Kinetic studies revealed that the inhibitory effect of LGA on Mi-CK was non-competitive in relation to phosphocreatine. Finally, we verified that the inhibitory effect of LGA on tCK was fully prevented by pre-incubation of the homogenates with reduced glutathione (GSH), suggesting that this inhibition is possibly mediated by oxidation of essential thiol groups of the enzyme. Considering the importance of creatine kinase activity for energy homeostasis, our results suggest that the selective inhibition of this enzyme activity by increased levels of LGA could be possibly related to the cerebellar degeneration characteristically found in patients affected by L-2-hydroxyglutaric aciduria.
L-2-hydroxyglutaric acid (LGA) is the biochemical hallmark of L-2-hydroxyglutaric aciduria (L-OHGA), an inherited neurometabolic disorder characterized by progressive neurodegeneration with cerebellar and pyramidal signs, mental deterioration, epilepsy, and subcortical leukoencephalopathy. Because the underlying mechanisms of the neuropathology of this disorder are virtually unknown, in this study we tested the in vitro effect of LGA on various parameters of oxidative stress, namely, chemiluminescence, thiobarbituric acid-reactive substances (TBA-RS), protein carbonyl formation (PCF), total radical-trapping antioxidant potential (TRAP), total antioxidant reactivity (TAR), and the activities of the antioxidant enzymes catalase, glutathione peroxidase, and superoxide dismutase in cerebellum and cerebral cortex of 30-day-old rats. LGA significantly increased chemiluminescence, TBA-RS, and PCF measurements and markedly decreased TAR values in cerebellum, in contrast to TRAP and the activity of the antioxidant enzymes, which were not altered by the acid. Similar but less pronounced effects were provoked by LGA in cerebral cortex. Moreover, the LGA-induced increase of TBA-RS was significantly attenuated by melatonin (N-acetyl-5-methoxytryptamine) and by the combinations of ascorbic acid plus Trolox (soluble alpha-tocopherol) and of superoxide dismutase plus catalase but not by the inhibitor of nitric oxide synthase Nomega-nitro-L-arginine methyl ester (L-NAME), creatine, or superoxide dismutase or catalase alone in either cerebral structure. The data indicate that LGA provokes oxidation of lipids and proteins and reduces the brain capacity to modulate efficiently the damage associated with an enhanced production of free radicals, possibly by inducing generation of superoxide and hydroxyl radicals, which are trapped by the scavengers used. Thus, in case these findings can be extrapolated to human L-OHGA, it may be presumed that oxidative stress is involved in the pathophysiology of the brain damage observed in this disorder.
Brain tumours in adults are a rare disease from which survival is generally poor compared to many other cancers. Reports of rising trends need to be cautiously interpreted as they may well be explained by changes in diagnostic and clinical practice. In childhood a different profile of tumour types is present and survival has improved over recent years and is higher than in adults. Apart from genetic predisposition, the most well established environmental risk factor for brain tumours is exposure to high doses of ionising radiation. Research into infections and immune factors may prove a fruitful avenue of investigation.
Employing lymphoblasts derived from two non related patients with L-2-HG aciduria, we examined the origin of L-2-hydroxyglutaric acid (L-2-HG) through incubation with [(13)C6]glucose and [(2)H5]glutamic acid. Formation of labelled 2-ketoglutaric acid (2-KG), citric acid and L-2-HG was determined by GC-MS. The quantitative and qualitative isotopomer pattern following incubation with [(13)C6]glucose was identical for all end-products. Incubations with [(2)H5]glutamic acid as precursor revealed the formation of identical isotopomers for 2-KG and L-2-HG. Our data indicate that 2-KG is the metabolic precursor of L-2-HG, adding to previous studies which revealed that 2-KG is the metabolic precursor of D-2-HG. These data suggest that 2-KG has a pathophysiological role in combined D/L-2-HG aciduria.
L-2-Hydroxyglutaric aciduria (L-2-OHGA) is a rare autosomal recessive neurometabolic disease linked to chromosome 14q21.1 and is caused by mutations in the gene that most likely encodes L: -2-hydroxyglutarate dehydrogenase, which normally catalyses L: -2-hydroxyglutarate to alpha-ketoglutarate. It is characterized by progressive mental deterioration, pyramidal and cerebellar syndromes, macrocephaly and marked polycystic white-matter degeneration mainly involving frontal lobes. Brain tumours of variable nature have frequently been observed in L-2-OHGA. We report a patient affected by this disease who at the age of 20 years developed a bone tumour involving the right frontal region of the calvaria. He had first presented at the age of 10 years with psychomotor delay, clumsy gait and moderate mental impairment. Examination showed macrocephaly, cerebellar ataxia and quadripyramidal syndrome. Brain MRI showed low signal intensities on T1-weighted images and high signal intensities on T2-weighted images in cerebral subcortical white matter. Serum and urinary amino acid assay was normal. Urinary 2-hydroxyglutaric acid was 1418 mmol/mol creatinine (controls <25). Analysis of the L-2-hydroxyglutarate dehydrogenase gene revealed a homozygous mutation in exon 2 (A320G). At the age of 20 years, an osteoma of the right frontal bone was diagnosed. This finding reinforces the opinion concerning the association of L-2-OHGA and tumorigenesis and prompted us to verify the possible responsibility of some overproduced substances in this disease for the development of tumours and to look for any correlation between the type of mutation in the L-2-OHGA gene and the tumorigenic potential observed in some patients affected by this disease.
l-2-Hydroxyglutaric aciduria (l-2-HGA) is a hereditary neurometabolic disorder reported in human beings and dogs. An 11-month-old Staffordshire bull terrier was suspected to have the disease, on the basis of clinical signs and magnetic resonance imaging findings. l-2-HGA was confirmed by urinary organic analysis and DNA testing and the dog was humanely destroyed. Post-mortem findings consisted only of microscopical lesions in the brain, characterized by marked spongiform changes and predominantly affecting the grey matter of the cerebral cortex, thalamus, cerebellum and brainstem. The spongiform changes were characterized by well-demarcated, clear vacuoles located at perineuronal and perivascular sites. Immunohistochemical and ultrastructural examination confirmed that the affected cells were astrocytes.
L-2-hydroxyglutaric aciduria (LHGuria) is a rare neurometabolic disorder, which has characteristic clinical and laboratory features. The recent findings imply that LHG dehydrogenase is responsible for the disease and is FAD-dependent. Therefore, it might be expected that riboflavin could enhance any residual activity. We present our observations from nearly 2-year-long riboflavin treatment in a 16-year-old boy with LHGuria. During riboflavin treatment of 100 mg/d, partial improvement in his cognitive and motor performances was observed. Urinary LHG excretion decreased from 5990 mmol/mol creatinine to 1490 mmol/mol creatinine. Moreover, when riboflavin treatment was interrupted, significant disturbances in both symptoms and urinary LHG excretion (6360 mmol/mol creatinine) occurred in the patient. After the resettlement of riboflavine treatment, the patient resumed to his previous clinical status in a week. The improvement went further minimally under the dose of 200mg/d, but no further improvement happened with 300 mg/d. The present case suggests that riboflavin could be considered as a potential therapeutic approach in LHGuria until the optimal treatment of LHGuria is established.