Transmission disequilibrium study of an oligodendrocyte and myelin glycoprotein gene allele in 431 families with an autistic proband.

Autistic disorder is a neurodevelopmental disorder where genetic factors play an important role. We previously described an association between a subgroup of French autistic patients and an allele of a non-synonymous single nucleotide polymorphism (nsSNP: OMGP62 G>A or rs11080149) in the gene coding for the oligodendrocyte and myelin glycoprotein (OMG), located at 7Mb from the marker D17S250, linked to autism in two independent genome scan studies. We report a study on 431 families with 1 affected child from different origins: French Canada (n=262), Italy (n=123) and United States (n=46). We analyzed the transmission of the rs11080149 alleles from parents to their affected children. There was a preferential transmission of the G allele from parents to affected children (p=0.0017) in the overall sample. Paternal and maternal transmission rates were both skewed. Taking into account our previous results obtained in a French group of patients, where we observed an association with allele A, a direct role of this polymorphism is improbable in autism. The associations observed in Japanese and French patients, the linkage studies and the present work speak in favor of the existence of a susceptibility gene for autism in the NF1 locus.