[Show abstract][Hide abstract]ABSTRACT: Mitochondrial complex I is the largest multi-protein enzyme complex of the oxidative phosphorylation system. Seven subunits of this complex are encoded by the mitochondrial and the remainder by the nuclear genome. We review the natural disease course and signs and symptoms of 130 patients (four new cases and 126 from literature) with mutations in nuclear genes encoding structural complex I proteins or those involved in its assembly. Complex I deficiency caused by a nuclear gene defect is usually a non-dysmorphic syndrome, characterized by severe multi-system organ involvement and a poor prognosis. Age at presentation may vary, but is generally within the first year of life. The most prevalent symptoms include hypotonia, nystagmus, respiratory abnormalities, pyramidal signs, dystonia, psychomotor retardation or regression, failure to thrive, and feeding problems. Characteristic symptoms include brainstem involvement, optic atrophy and Leigh syndrome on MRI, either or not in combination with internal organ involvement and lactic acidemia. Virtually all children ultimately develop Leigh syndrome or leukoencephalopathy. Twenty-five percent of the patients died before the age of six months, more than half before the age of two and 75 % before the age of ten years. Some patients showed recovery of certain skills or are still alive in their thirties . No clinical, biochemical, or genetic parameters indicating longer survival were found. No clear genotype-phenotype correlations were observed, however defects in some genes seem to be associated with a better or poorer prognosis, cardiomyopathy, Leigh syndrome or brainstem lesions.
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Full-text Article · May 2012 · Journal of Inherited Metabolic Disease
[Show abstract][Hide abstract]ABSTRACT: A new methodology to prepare lyophilisomes (self-assembled vesicles composed of phospholipids), which are known as biocapsules, from a range of biomolecules was investigated. The samples used included elastin, acetic acid and liquid nitrogen. The technique involved freezing, annealing, and lyophilization procedure. The transmission electron microscopy (TEM) unveiled the capsule nature of the spheres. The walls of the capsules were found to be smooth with equal distribution of protein over it. Fast-freezing in liquid N2 initiated a micro-phase separation between the bulk of the water and an elastin/acetic acid/water compartment. The transition of the spheres into capsules took place due to coffee-stain mechanism, which explains the formation of solid, ringlike stains from solution droplets. The technique offers enough flexibility and is useful for the development of new biocapsules.
[Show abstract][Hide abstract]ABSTRACT: Defective control of the alternative route of the complement system is an important cause of the non-diarrhoea haemolytic uraemic syndrome (HUS). On the endothelial surface, mutations in HF1, MCP and IF predispose to development ofHUS. Uncontrolled complement activation on the surface of endothelial cells will damage these cells extensively. Plasmapheresis can be an effective, although temporary, treatment for mutations in HF1 and IF. HUS frequently recurs after renal transplantation in patients with HF1 or IF mutations but not in patients with a mutation of MCP. These genetic defects can be detected by routine diagnostics.
Article · Feb 2007 · Nederlands tijdschrift voor geneeskunde
[Show abstract][Hide abstract]ABSTRACT: Dermatan sulfate (DS) is a member of the glycosaminoglycan (GAG) family and is primarily located in the extracellular matrix. Using a modified phage display procedure, we selected 2 different antibodies against DS of which one antibody, LKN1, was specific for DS. LKN1 was especially reactive with 4/2,4-di-O-sulfated DS, and did not react with other classes of GAGs including chondroitin sulfate and heparan sulfate. Immunohistochemical analysis of kidney, skin and tendon showed a typical fibrillar staining pattern, co-localizing with type I collagen. Staining was abolished by specific enzymatic digestion of DS. Immunoelectron microscopy confirmed the association of the DS epitope with collagen fibrils. The location of DS did not follow the main banding period of collagen, which is in line with the current concept that the core protein rather than the DS moiety of DS-proteoglycans specifically binds to collagen fibrils. This unique anti-DS antibody and the availability of its coding DNA may be instrumental in studies of the structure and function of DS.
[Show abstract][Hide abstract]ABSTRACT: In a 17-year-old woman with absent sexual development and a congenital nephrotic syndrome leading to renal failure, the Denys-Drash syndrome was diagnosed after development of an ovarian dysgerminoma. The Denys-Drash syndrome is characterised by the triad: progressive nephropathy due to diffuse mesangial sclerosis, male pseudo-hermaphroditism (XY karyotype with ambiguous or female genital organs) and an increased risk of developing Wilms' tumour and gonadoblastoma. The syndrome is generally caused by a genetic defect in the Wilms' tumour suppressor 1 gene (WT1 gene). A WT1 mutation and XY karyotype were also found in this patient. The WT1 gene encodes a transcription factor playing an important role in renal and genital development. The diagnosis of Denys-Drash syndrome had important consequences for the follow-up and treatment of the patient. The second gonad and the native kidneys were removed due to the increased risk of malignancy. Moreover, the finding of a XY karyotype could result in serious psychic problems. Physicians responsible for the health of adults are confronted more and more often with the consequences of childhood diseases. This case illustrates the necessity to inform such physicians about previously untreatable genetic diseases of childhood so that the adequate medical management of these patients can be guaranteed.
Article · Aug 2005 · Nederlands tijdschrift voor geneeskunde
[Show abstract][Hide abstract]ABSTRACT: The heterogeneity of mitochondrial cytopathies is characteristic for this group of disorders, which preferentially affect the muscle and nerve system. The A3243G transition in the tRNA(Leu(UUR)) gene has been associated with slowly progressive forms of focal segmental glomerulosclerosis (FSGS). Here we present a patient who developed a severe nephrotic syndrome during her first pregnancy, which persisted after delivery, and proved resistant to immunosuppressive therapy. A sister of our patient had developed diabetes mellitus. We analysed the DNA for the presence of the mitochondrial DNA (mtDNA) A3243G transition.
DNA was isolated from peripheral blood leukocytes and urine sediments. Polymerase chain reaction was performed to amplify the mtDNA. Restriction enzyme analysis was used to detect the presence of the A3243G transition. Quantitative analysis of the A3243G mutation was done using the pyrosequencing technique.
Quantitative analysis revealed a proportion of mutated mtDNA of 30% in the leukocytes and 68% in the urine sediments of the proband. On further analysis, we also found the transition in the mother, the diabetic sister and the daughter of the proband.
MtDNA abnormalities can cause a steroid-resistant nephrotic syndrome, histologically characterized by FSGS. Physicians should be especially mindful of mitochondrial abnormalities when hearing loss, diabetes mellitus or neuromuscular disorders are present in the patient or family members.
Article · Mar 2005 · Nephrology Dialysis Transplantation
[Show abstract][Hide abstract]ABSTRACT: Nijmegen breakage syndrome (NBS) is an autosomal recessive disorder, due to defects in the NBS1 gene and belongs to the DNA repair disorders. We report neuropathological findings of the first ever recognised case of the about 60 described cases of NBS. This patient showed severe microcephaly with a simplified gyral pattern especially in the frontal lobes. There were no signs of a degenerative disease, or of a primary migration disorder. A bulge on top of the corpus callosum, most probably a very large remnant of the involuting striae longitudinales mediales et laterales, was found. This can be considered as an incomplete development of limbic structures. The severe diminishment of neocortical neurones suggests an important role for the NBS1 gene in corticogenesis in man, as suggested earlier in animal studies of other DNA-repair genes.
[Show abstract][Hide abstract]ABSTRACT: Familial forms of steroid-resistant nephrotic syndrome with the histologic findings of focal-segmental glomerulosclerosis have frequently a genetic basis. For the non-familial forms this is still unresolved.
Ten children with non-familial steroid-resistant nephrotic syndrome along with focal-segmental glomerulosclerosis were tested for mutations in the WT-1 and NPHS2 genes.
In 1 patient, a mutation in intron 9 of the WT-1 gene and in 1 patient a heterozygous NPHS2 mutation could be detected. Both abnormalities are important for the treatment modalities and prognosis.
Additional studies will have to provide a solid basis for the recommendation of mutation analysis in non-familial steroid-resistant focal-segmental glomerulosclerosis.
[Show abstract][Hide abstract]ABSTRACT: A comparison of the clinical presentation, disease course and results of laboratory and imaging studies of all patients so far published with a NDUFS4 mutation are presented. This reveals marked clinical heterogeneity, even in patients with the same genotype.
Full-text Article · Feb 2003 · Journal of Inherited Metabolic Disease
[Show abstract][Hide abstract]ABSTRACT: We report a branch site mutation in the gene of the enzyme tyrosine hydroxylase (TH): a −24t > a substitution two bases upstream of the adenosine in the branchpoint sequence (BPS) of intron 11. As normal lariat formation is therefore prevented, alternative splicing takes place: use of the BPS of intron 12 results in skipping of exon 12, whereas the use of a cryptic branch site in intron 11 leads to partial retention of this intron in the mRNA. This leads in both cases to an aberrant protein product. In the one case, skipping of exon 12 results in the absence of 32 amino acids. In the other, retention of 36 nucleotides of intron 11 in the mRNA results in the incorporation of twelve additional amino acids. The functional consequences of this mutation for the patient, who is also heterozygous for another previously identified mutation, become apparent in a severe clinical phenotype.
[Show abstract][Hide abstract]ABSTRACT: In this paper we give a summary of data on cerebrotendinous xanthomatosis (CTX). In The Netherlands 41 patients have been diagnosed until now. The disease has been studied in the Eighties in Groningen resulting in the thesis of Koopman (1). Two-hundred CTX cases have been described in the literature. The diagnosis is missed in many patients because clinicians insufficiently recognize the clinical signs and symptoms. The paper gives a historical overview of the clinical symptoms and deals with the pathophysiology of CTX, the methodology to diagnose CTX, the underlying genetic defect, and the therapy for CTX.
[Show abstract][Hide abstract]ABSTRACT: Inherited renal tubular disorders associated With hypokalemic alkalosis (Bartter-like syndromes) can be subdivided into at least three clinical phenotypes: (i) the hypocalciuric-hypomagnesemic Gitelman variant; (ii) the classic variant; and (iii) the antenatal hypercalciuric variant (also termed hyperprostaglandin E syndrome). Mutations in the Na-CI cotransporter (NCCT) underlie the pathogenesis of the Gitelman variant and mutations in the Na-K-2Cl cotransporter (NKCC2) have recently been identified in the antenatal hypercalciuric variant. We now describe mutations in the gene encoding the inwardly-rectifying potassium channel, ROMK, in eight kindreds with the antenatal variant of Bartter syndrome. These findings indicate that antenatal Bartter syndrome is genetically heterogeneous and provide new insights into the molecular pathogenesis of Bartter-like syndromes.
[Show abstract][Hide abstract]ABSTRACT: This report concerns two new mutations in the sterol 27-hydroxylase gene in two patients with cerebrotendinous xanthomatosis
(CTX). In a Surinam-Creole patient (patient A), a G deletion on position cDNA 546/547 in exon 3 led to a frameshift and the
introduction of a premature termination codon. In a Dutch patient (patient B), a C→T transition at position 496 in exon 3
also led to a premature termination codon. Patient A was homozygous for the mutation, whereas patient B was compound heterozygous,
a C→T transition also being found in exon 6 at position 1204. The two new mutations were confirmed by restriction analysis
with the restriction enzymes FokI and MaeI, respectively.