Adenylosuccinate lyase deficiency is a disease of purine metabolism which affects patients both biochemically and behaviorally. The symptoms are variable and include psychomotor retardation, autistic features, hypotonia, and seizures. Patients also accumulate the substrates of ADSL in body fluids. Both the presence of normal levels of ADSL enzyme activities in some patient tissues and the absence of a clear correlation between mutations, biochemistry, and behavior show that the system has unexplored biochemical and/or genetic complexity. It is unclear whether the pathological mechanisms of this disease result from a deficiency of purines, a toxicity of intermediates, or perturbation of another pathway or system. A patient with autistic features and mild psychomotor delay carries two novel mutations in this gene, E80D and D87E. The creation of a mouse model of this disease will be an important step in elucidating the in vivo mechanisms of the disease. Mice carrying mutations that cause ADSL deficiency in humans will be informative as to the effects of these mutations both during embryogenesis and on the brain, possibly leading to therapies for this disease in the future.
"Patients have a unique behavioral phenotype including excessive laughter, a very happy disposition, and stereotyped movements mimicking Angelman syndrome . Patients show a variable combination of mental retardation, epilepsy, ASD features, and cerebellar vermis hypoplasia  . This disorder can be diagnosed using the Bratton–Marshall assay to measure succinylaminoimidazole carboxamide riboside and succinyladenosine concentration in the urine and/or cerebrospinal fluid. "
[Show abstract][Hide abstract] ABSTRACT: Autism spectrum disorder (ASD) affects a significant number of individuals in the United States, with the prevalence continuing to grow. A significant proportion of individuals with ASD have comorbid medical conditions such as epilepsy. In fact, treatment-resistant epilepsy appears to have a higher prevalence in children with ASD than in children without ASD, suggesting that current antiepileptic treatments may be suboptimal in controlling seizures in many individuals with ASD. Many individuals with ASD also appear to have underlying metabolic conditions. Metabolic conditions such as mitochondrial disease and dysfunction and abnormalities in cerebral folate metabolism may affect a substantial number of children with ASD, while other metabolic conditions that have been associated with ASD such as disorders of creatine, cholesterol, pyridoxine, biotin, carnitine, γ-aminobutyric acid, purine, pyrimidine, and amino acid metabolism and urea cycle disorders have also been associated with ASD without the prevalence clearly known. Interestingly, all of these metabolic conditions have been associated with epilepsy in children with ASD. The identification and treatment of these disorders could improve the underlying metabolic derangements and potentially improve behavior and seizure frequency and/or severity in these individuals. This paper provides an overview of these metabolic disorders in the context of ASD and discusses their characteristics, diagnostic testing, and treatment with concentration on mitochondrial disorders. To this end, this paper aims to help optimize the diagnosis and treatment of children with ASD and epilepsy. This article is part of a Special Issue entitled "Autism and Epilepsy".
"Other reported patients were from Czech Republic (Kmoch et al 2000; Mouchegh et al 2007), Poland (Jurecka et al 2008a, b), Germany (Kohler et al 1999; Mouchegh et al 2007), UK (Lundy et al 2010), Spain (Castro et al 2002; Perez-Duenas et al 2011), Italy (Nassogne et al 2000; Race et al 2000), Portugal (Edery et al 2003), France (Holder-Espinasse et al 2002), Norway (Marie et al 2002), Turkey (Kmoch et al 2000; Spiegel et al 2006), Morocco (Jaeken and Van den Berghe 1984; Stone et al 1992; Gitiaux Fig. 1 De novo purine biosynthesis pathway. Abbreviations are as follows: PRPP, phosphoribosylpyrophosphate; SAICAR, succinylaminoimidazole carboxamide ribotide; SAICAr, succinylaminoimidazole carboxamide riboside; AICAR, aminoimidazole carbozamide ribotide; FAICAR, formyloaminoimidazole carboxamide ribotide; IMP, inosine monophosphate; S-AMP, adenylosuccinate; S-Ado, succinyladenosine; AMP, adenine monophosphate; XMP, xanthine monophosphate; GMP, guanine monophosphate; ADSL, adenylosuccinate lyase; AICAR TF, aminoimidazole carboxamide riboside transformylase; IMP CH, inosine monophosphate cyclohydrolase; ATIC, bifunctional enzyme AICAR transformylase/IMP cyclohydrolase et al 2009), Malaysia (Chen et al 2010), Australia (Stathis et al 2000; van Werkhoven et al 2013), Colombia (Castro et al 2002), and the US (Kmoch et al 2000; Spiegel et al 2006). Detailed and regularly updated information on identified patients may be found on ADSL database http://www1.lf1.cuni. "
[Show abstract][Hide abstract] ABSTRACT: Adenylosuccinate lyase ADSL) deficiency is a defect of purine metabolism affecting purinosome assembly and reducing metabolite fluxes through purine de novo synthesis and purine nucleotide recycling pathways. Biochemically this defect manifests by the presence in the biologic fluids of two dephosphorylated substrates of ADSL enzyme: succinylaminoimidazole carboxamide riboside (SAICAr) and succinyladenosine (S-Ado). More than 80 individuals with ADSL deficiency have been identified, but incidence of the disease remains unknown. The disorder shows a wide spectrum of symptoms from slowly to rapidly progressing forms. The fatal neonatal form has onset from birth and presents with fatal neonatal encephalopathy with a lack of spontaneous movement, respiratory failure, and intractable seizures resulting in early death within the first weeks of life. Patients with type I (severe form) present with a purely neurologic clinical picture characterized by severe psychomotor retardation, microcephaly, early onset of seizures, and autistic features. A more slowly progressing form has also been described (type II, moderate or mild form), as having later onset, usually within the first years of life, slight to moderate psychomotor retardation and transient contact disturbances. Diagnosis is facilitated by demonstration of SAICAr and S-Ado in extracellular fluids such as plasma, cerebrospinal fluid and/or followed by genomic and/or cDNA sequencing and characterization of mutant proteins. Over 50 ADSL mutations have been identified and their effects on protein biogenesis, structural stability and activity as well as on purinosome assembly were characterized. To date there is no specific and effective therapy for ADSL deficiency.
"Adenylosuccinate lyase deficiency results in accumulation of succinylpurines leading to psychomotor retardation , autistic features, hypotonia, and seizures [Spiegel et al., 2006]. Motor apraxia, severe speech deficits, excessive laughter, a very happy disposition, hyperactivity, a short attention span, mouthing of objects, tantrums, and stereotyped movements have been reported in female sibs by Gitiaux et al. . "
[Show abstract][Hide abstract] ABSTRACT: The Angelman syndrome is caused by disruption of the UBE3A gene and is clinically delineated by the combination of severe mental disability, seizures, absent speech, hypermotoric and ataxic movements, and certain remarkable behaviors. Those with the syndrome have a predisposition toward apparent happiness and paroxysms of laughter, and this finding helps distinguish Angelman syndrome from other conditions involving severe developmental handicap. Accurate diagnosis rests on a combination of clinical criteria and molecular and/or cytogenetic testing. Analysis of parent-specific DNA methylation imprints in the critical 15q11.2-q13 genomic region identifies 75-80% of all individuals with the syndrome, including those with cytogenetic deletions, imprinting center defects and paternal uniparental disomy. In the remaining group, UBE3A sequence analysis identifies an additional percentage of patients, but 5-10% will remain who appear to have the major clinical phenotypic features but do not have any identifiable genetic abnormalities. Genetic counseling for recurrence risk is complicated because multiple genetic mechanisms can disrupt the UBE3A gene, and there is also a unique inheritance pattern associated with UBE3A imprinting. Angelman syndrome is a prototypical developmental syndrome due to its remarkable behavioral phenotype and because UBE3A is so crucial to normal synaptic function and neural plasticity.
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