1. Ming X, Johnson WG, Stenroos ES, Mars A, Lambert GH, Buyske S. {{Genetic variant of glutathione peroxidase 1 in autism}}. {Brain Dev};2009 (Feb 3)
Genetic factors can contribute to autistic disorder (AD). Abnormal genes of oxidative stress pathways and increased oxidative stress have been reported in autism spectrum disorders. Polymorphisms of genes involved in glutathione metabolism, e.g. GSTP1 and GSTM1 are reportedly associated with autistic disorder. We investigated a GCG repeat polymorphism of a human glutathione peroxidase (GPX1) polyalanine repeat (ALA5, ALA6 and ALA7) in 103 trios of AD (probands and parents) using the transmission disequilibrium test. Significant transmission disequilibrium (p=0.044) was found in the overall transmission of the three alleles. The ALA6 allele was under transmitted (p=0.017). These results suggest that possessing this ALA6 allele may be protective for AD. Future study of interaction of the GPX1 GCG repeat and other gene polymorphisms such as the MnSOD ALA16 or the GPX1 Pro198Leu polymorphism in this cohort of AD families may shed light in whether the combination of the ALA6 allele with another polymorphism of antioxidant allele contributes to the increased oxidative stress in autism.
2. Molloy CA, Murray DS, Kinsman A, Castillo H, Mitchell T, Hickey FJ, Patterson B. {{Differences in the clinical presentation of Trisomy 21 with and without autism}}. {J Intellect Disabil Res};2009 (Feb);53(2):143-151.
BACKGROUND: Autism occurs 10 times more often in children with Down syndrome than in the general population, but diagnosing co-occurring autism in Down syndrome with severe intellectual disability is challenging. The objective of this case-control study was to identify characteristics differentiating children with trisomy 21 with and without autism and to determine the extent to which severe cognitive impairment affects the measures of autism symptomatology. METHOD: Twenty children with trisomy 21 and autism (cases) were compared with children with trisomy 21 without autism (controls) matched on chronologic age, race and gender. Communication, cognitive and adaptive behaviour skills were assessed with standardized instruments. Medical history was reviewed and medical records were examined for early head growth. Scores on the diagnostic algorithm of the Autism Diagnostic Interview–Revised (ADI-R) were compared after adjusting for cognitive ability as measured by the Stanford-Binet (Fifth Edition) non-verbal change sensitive score. RESULTS: Cases performed significantly more poorly on all assessments. Mean case-control differences for matched pairs were all significant at P < 0.0001 for receptive and expressive language skills, cognitive skills and adaptive skills. Seven cases had a history of seizures compared with one control(P = 0.01). After adjusting for cognitive ability, the mean scores on the Reciprocal Social Interaction, Communication, and Restricted, Repetitive and Stereotyped Behaviours domains of the ADI-R diagnostic algorithm remained significantly higher in cases compared with controls (P < 0.0001). All participants had decreased head size consistent with Down syndrome, with no case-control differences. CONCLUSION: Children with trisomy 21 and autism have significantly more impaired brain function than children with trisomy 21 without autism. However, the deficits in the core domains of social reciprocity and communication, and the restricted and repetitive interests are not entirely explained by the more severe cognitive impairment. This autism phenotype in children with trisomy 21 which includes an increased risk for seizures may indicate a widespread loss of functional connectivity in the brain.
3. Nakashima N, Yamagata T, Mori M, Kuwajima M, Suwa K, Momoi MY. {{Expression analysis and mutation detection of DLX5 and DLX6 in autism}}. {Brain Dev};2009 (Feb 3)
Linkage analysis has reported the chromosomal region 7q21 to be related with autism. This region contains an imprinting region with MECP2-binding sites, and DLX5 is reported to be modulated by MECP2. DLX5 and adjacent DLX6 are homeobox genes working in neurogenesis. From these points, DLX5 and DLX6 are candidate genes for autism. Therefore, we analyzed the expression of DLX5 and DLX6, and also PEG10 as a control in the lymphoblasts of autistic spectrum disorder (ASD) patients by real-time PCR to identify potential abnormality of expression. And we also analyzed DLX5 and DLX6 on ASD patients for mutation by direct sequence. The expression level of DLX5 was not different between ASD and controls but was higher in four ASD patients compared to controls. Clinical features of these four patients were variable. DLX5 expression was biallelic in two ASD patients and two controls, indicating that DLX5 was not imprinted. There was no mutation in DLX5 in ASD. Although DLX5 was not likely to play major role in ASD, genes relating to DLX5 expression and downstream of DLX5 are considered to be candidate genes for some of the ASD patients. In DLX6, we detected a G656A base change (R219H) in two ASD patients who were male siblings. DLX6 may contribute to the pathogenesis of ASD.
