Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004352 (autism)
 32,579 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT) activities were measured in cells from children with autism (n = 5) and the Gilles de la Tourette syndrome (n = 5). Monoamine oxidase activities in cultured skin fibroblasts (type A) and platelets (type B) from the same individual were not correlated. COMT activities in fibroblasts and red blood cells showed a negative but not significant correlation (r = -0.42). Fibroblast MAO and COMT activities from patients were similar to values from controls matched for age, race, and sex. Increasing clinical severity of illness in both disorders, however, correlated significantly with higher fibroblast MAE activity. Cultured fibroblasts provide a means of measuring enzyme activities independently of the individual's current physiological and psychological state.
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PMID:Monoamine oxidase and catechol-O-methyltransferase activities in cultured fibroblasts and blood cells from children with autism and the Gilles de la Tourette syndrome. 693 62

We have examined three functional polymorphisms, serotonin transporter promoter region polymorphism (5-HTTLPR), dopamine D4 exon III repeat region (DRD4), and catechol-O-methyltransferase (COMT), in a small family-based design toward identifying candidate genes that confer risk for autism. A significant excess of the long/long 5-HTTLPR genotype was observed (likelihood ratio = 7.18; P = 0.027; 2 df; n = 33 families) as well as preferential transmission of the long allele of the 5-HTTLPR (TDT chi-square = 5.44; P<0.025; 1 df). No association was observed between the COMT and DRD4 polymorphisms and autism in this sample. Some previous studies have observed linkage between autism and the 5-HTTLPR polymorphism and the current results are similar to those first reported by Klauck et al. [1997: Hum Genet 100:224-229; 1997: Hum Mol Genet 6:2233-2238]. Additionally, elevated serotonin levels have been consistently found in 30%-50% of autistic patients and may represent a marker for familial autism. Hyperserotonemia in autism appears to be due to enhanced 5-HT uptake, as free 5-HT levels are normal and the current report of an excess of the long/long 5-HTTLPR genotype in autism could provide a partial molecular explanation for high platelet serotonin content in autism.
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PMID:Evidence for an association with the serotonin transporter promoter region polymorphism and autism. 1137 54

We present a multilevel approach to developing potential explanations of cognitive impairments and psychopathologies common to individuals with chromosome 22q11.2 deletion syndrome. Results presented support our hypothesis of posterior parietal dysfunction as a central determinant of characteristic visuospatial and numerical cognitive impairments. Converging data suggest that brain development anomalies, primarily tissue reductions in the posterior brain and changes to the corpus callosum, may affect parietal connectivity. Further findings indicate that dysfunction in "frontal" attention systems may explain some executive cognition impairments observed in affected children, and that there may be links between these domains of cognitive function and some of the serious psychiatric conditions, such as attention-deficit/hyperactivity disorder, autism, and schizophrenia, that have elevated incidence rates in the syndrome. Linking the neural structure and the cognitive processing levels in this way enabled us to develop an elaborate structure/function mapping hypothesis for the impairments that are observed. We show also, that in the case of the catechol-O-methyltransferase gene, a fairly direct relationship between gene expression, cognitive function, and psychopathology exists in the affected population. Beyond that, we introduce the idea that variation in other genes may further explain the phenotypic variation in cognitive function and possibly the anomalies in brain development.
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PMID:A multilevel analysis of cognitive dysfunction and psychopathology associated with chromosome 22q11.2 deletion syndrome in children. 1626 91

Autism is a behaviorally defined neurodevelopmental disorder usually diagnosed in early childhood that is characterized by impairment in reciprocal communication and speech, repetitive behaviors, and social withdrawal. Although both genetic and environmental factors are thought to be involved, none have been reproducibly identified. The metabolic phenotype of an individual reflects the influence of endogenous and exogenous factors on genotype. As such, it provides a window through which the interactive impact of genes and environment may be viewed and relevant susceptibility factors identified. Although abnormal methionine metabolism has been associated with other neurologic disorders, these pathways and related polymorphisms have not been evaluated in autistic children. Plasma levels of metabolites in methionine transmethylation and transsulfuration pathways were measured in 80 autistic and 73 control children. In addition, common polymorphic variants known to modulate these metabolic pathways were evaluated in 360 autistic children and 205 controls. The metabolic results indicated that plasma methionine and the ratio of S-adenosylmethionine (SAM) to S-adenosylhomocysteine (SAH), an indicator of methylation capacity, were significantly decreased in the autistic children relative to age-matched controls. In addition, plasma levels of cysteine, glutathione, and the ratio of reduced to oxidized glutathione, an indication of antioxidant capacity and redox homeostasis, were significantly decreased. Differences in allele frequency and/or significant gene-gene interactions were found for relevant genes encoding the reduced folate carrier (RFC 80G > A), transcobalamin II (TCN2 776G > C), catechol-O-methyltransferase (COMT 472G > A), methylenetetrahydrofolate reductase (MTHFR 677C > T and 1298A > C), and glutathione-S-transferase (GST M1). We propose that an increased vulnerability to oxidative stress (endogenous or environmental) may contribute to the development and clinical manifestations of autism.
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PMID:Metabolic endophenotype and related genotypes are associated with oxidative stress in children with autism. 1691 39

Attention-deficit/hyperactivity disorder (ADHD) is a highly disruptive childhood-onset disorder that often persists into adolescence and adulthood. Comorbidity with other problems, such as autism, dyslexia and conduct disorder (CD) is very common. Although little is known about the pathophysiology of ADHD, family, twin and adoption studies have shown that it is highly heritable. Whole genome linkage studies suggest there are no common susceptibility genes of moderate effect size. Most published research has been based on functional candidate gene studies. The most consistent evidence for association with ADHD relates to a dopamine D4 receptor (DRD4) gene variable number tandem repeat (VNTR), a dopamine D5 receptor (DRD5) gene microsatellite and a dopamine transporter (DAT1) gene VNTR. In addition, the catechol-O-methyltransferase (COMT) val158/108 met variant has been shown to increase risk for associated antisocial behavior. The first genome-wide association studies (GWAS) of ADHD have been completed and although larger studies are still required to detect common risk variants, novel risk pathways are being suggested for ADHD. Further research on the contribution of rare variants, larger genome-wide association and sequencing studies and ADHD phenotype refinement is now needed.
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PMID:Fitting the pieces together: current research on the genetic basis of attention-deficit/hyperactivity disorder (ADHD). 2085 18

Velocardiofacial (VCFS; 22q11.2 deletion) syndrome is a genetic disorder that results from a hemizygous deletion of the q11.2 region on chromosome 22, and is associated with greatly increased risk for psychiatric disorders, including autism spectrum disorder (ASD) and schizophrenia. There is emerging evidence for the involvement of catechol-O-methyltransferase (COMT) and proline dehydrogenase (oxidase) 1 (PRODH) in the psychiatric phenotype of individuals with VCFS. Here, we tested the hypothesis that PRODH and COMT are associated with ASD in youths with VCFS. We found that individuals with VCFS and the low-activity alleles of both PRODH and COMT (rs4819756A and rs4680A) were more likely to present with ASD as compared with individuals with VCFS and the high-activity alleles of these genes [P<0.05; odds ratio=6.0 (95% confidence interval=1.27-28.26; N=87)]. Our results suggest that PRODH and COMT may interact to contribute to the ASD phenotype in individuals with VCFS.
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PMID:Association between autism spectrum disorder in individuals with velocardiofacial (22q11.2 deletion) syndrome and PRODH and COMT genotypes. 2532 18