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| 2. |
- Betancur, Catalina, et al.
(författare)
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Serotonin transporter gene polymorphisms and hyperserotonemia in autistic disorder
- 2002
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Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 7:1, s. 67-71
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies have provided conflicting evidence regarding the association of the serotonin transporter (5-HTT) gene with autism. Two polymorphisms have been identified in the human 5-HTT gene, a VNTR in intron 21 and a functional deletion/insertion in the promoter region (5-HTTLPR) with short and long variants.2 Positive associations of the 5-HTTLPR polymorphism with autism have been reported by two family-based studies, but one found preferential transmission of the short allele3 and the other of the long allele.4 Two subsequent studies failed to find evidence of transmission disequilibrium at the 5-HTTLPR locus.5,6 These conflicting results could be due to heterogeneity of clinical samples with regard to serotonin (5-HT) blood levels, which have been found to be elevated in some autistic subjects.7–9 Thus, we examined the association of the 5-HTTLPR and VNTR polymorphisms of the 5-HTT gene with autism, and we investigated the relationship between 5-HTT variants and whole-blood 5-HT. The transmission/disequilibrium test (TDT) revealed no linkage disequilibrium at either loci in a sample of 96 families comprising 43 trios and 53 sib pairs. Furthermore, no significant relationship between 5-HT blood levels and 5-HTT gene polymorphisms was found. Our results suggest that the 5-HTT gene is unlikely to play a major role as a susceptibility factor in autism.
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| 3. |
- Jamain, Stéphane, et al.
(författare)
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Linkage and association of the glutamate receptor 6 gene with autism
- 2002
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Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 7:3, s. 302-310
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Tidskriftsartikel (refereegranskat)abstract
- A genome scan was previously performed and pointed to chromosome 6q21 as a candidate region for autism. This region contains the glutamate receptor 6 (GluR6 or GRIK2) gene, a functional candidate for the syndrome. Glutamate is the principal excitatory neurotransmitter in the brain and is directly involved in cognitive functions such as memory and learning. We used two different approaches, the affected sib-pair (ASP) method and the transmission disequilibrium test (TDT), to investigate the linkage and association between GluR6 and autism. The ASP method, conducted with additional markers on the 51 original families and in 8 new sibling pairs, showed a significant excess of allele sharing, generating an elevated multipoint maximum LOD score (ASPEX MLS = 3.28). TDT analysis, performed in the ASP families and in an independent data set of 107 parent-offspring trios, indicated a significant maternal transmission disequilibrium (TDTall P = 0.0004). Furthermore, TDT analysis (with only one affected proband per family) showed significant association between GluR6 and autism (TDT association P = 0.008). In contrast to maternal transmission, paternal transmission of GluR6 alleles was as expected in the absence of linkage, suggesting a maternal effect such as imprinting. Mutation screening was performed in 33 affected individuals, revealing several nucleotide polymorphisms (SNPs), including one amino acid change (M867I) in a highly conserved domain of the intracytoplasmic C-terminal region of the protein. This change is found in 8% of the autistic subjects and in 4% of the control population and seems to be more maternally transmitted than expected to autistic males (P = 0.007). Taken together, these data suggest that GluR6 is in linkage disequilibrium with autism.
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| 4. |
- Jamain, Stephane, et al.
(författare)
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Mutations of the X-linked genes encoding neuroligins NLGN3 and NLGN4 are associated with autism
- 2003
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 34:1, s. 27-29
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Tidskriftsartikel (refereegranskat)abstract
- Many studies have supported a genetic etiology for autism. Here we report mutations in two X-linked genes encoding neuroligins NLGN3 and NLGN4 in siblings with autism-spectrum disorders. These mutations affect cell-adhesion molecules localized at the synapse and suggest that a defect of synaptogenesis may predispose to autism.
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| 5. |
- Jamain, Stéphane, et al.
(författare)
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Y chromosome haplogroups in autistic subjects
- 2002
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Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 7:2, s. 217-219
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Tidskriftsartikel (refereegranskat)abstract
- The male to female ratio in autism is 4:1 in the global autistic population, but increases to 23:1 in autistic subjects without physical or brain abnormalities. 1 Despite this well-recognised gender difference, male predisposition to autistic disorder remains unexplained and the role of sex chromosomes is still debated. Numerical and structural abnormalities of the sex chromosomes are among the most frequently reported chromosomal disorders associated with autism. However, genome scans have failed to detect linkage on the X chromosome chromosome2–4 and this approach cannot study the non-recombining region of the Y chromosome. In this study, we searched for a specific Y chromosome effect in autistic subjects. Using informative Y-polymorphic markers, the Y chromosome haplotypes of 111 autistic subjects from France, Sweden and Norway were defined and compared with relevant control populations. No significant difference in Y- haplotype distribution between the affected and control groups was observed. Although this study cannot exclude the presence of a Y susceptibility gene, our results are not suggestive of a Y chromosome effect in autism.
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| 6. |
- Krebs, Marie-Odile, et al.
(författare)
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Absence of association between a polymorphic GGC repeat in the 5' untranslated region of the reelin gene and autism.
- 2002
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Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 7:7, s. 801-804
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Tidskriftsartikel (refereegranskat)abstract
- Autism is a complex neurodevelopmental disorder with severe cognitive and communication disabilities, that has a strong genetic predisposition predisposition.1 Reelin, a protein involved in neuronal migration during development, is encoded by a gene located on 7q22, 7q22,2 within the candidate region on 7q showing increased allele sharing in previous genome scans. 3–8 A case/control and family-based association study recently reported a positive association between a trinucleotide repeat polymorphism (GGC) located in the 5′ untranslated region (UTR) of the reelin gene and autism. 9 We performed a transmission disequilibrium test (TDT) analysis of the 5′UTR polymorphism in 167 families including 218 affected subjects (117 trios and 50 affected sib pairs) and found no evidence of linkage/association. Our results do not support previous findings and suggest that the reelin gene is unlikely to play a major role as a susceptibility factor in autism and/or genetic heterogeneity.
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| 7. |
- Philippe, Anne, et al.
(författare)
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Analysis of ten candidate genes in autism by association and linkage
- 2002
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Ingår i: American Journal of Medical Genetics. - : Wiley. - 0148-7299. ; 114:2, s. 125-128
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Tidskriftsartikel (refereegranskat)abstract
- We studied the possible involvement of ten candidate genes in autism: proenkephalin, prodynorphin, and proprotein convertase subtilisin/kexin type 2 (opioid metabolism); tyrosine hydroxylase, dopamine receptors D2 and D5, monoamine oxidases A and B (monoaminergic system); brain-derived neurotrophic factor, and neural cell adhesion molecule (involved in neurodevelopment). Thirty-eight families with two affected siblings and one family with two affected half-siblings, recruited by the Paris Autism Research International Sibpair Study (PARIS), were tested using the transmission disequilibrium test and two-point affected sib-pair linkage analysis. We found no evidence for association or linkage with intragenic or linked markers. Our family sample has good power for detecting a linkage disequilibrium of 0.80. Thus, these genes are unlikely to play a major role in the families studied, but further studies in a much larger sample would be needed to highlight weaker genetic effects.
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