Although there is considerable evidence for a strong genetic component to idiopathic autism, several genome-wide screens for susceptibility genes have been carried out with limited concordance of linked loci, reflecting either numerous genes of weak effect and/or sample heterogeneity. We studied the effect of restricting a sample of autism affected relative pairs to those with delayed (> 36 months) onset of phrase speech on evidence for linkage. In the second stage of a two-stage genome screen for susceptibility loci involving 95 families with two or more individuals with autism or related disorders, we observed a maximal multipoint heterogeneity LOD score (HLOD) of 1.96 and a maximal multipoint NPL score of 2.39 on chromosome 2q. Restricting the analysis to the subset of families (n = 49) with two or more individuals with a narrow diagnosis of autism and delayed onset of phrase speech generated a maximal multipoint heterogeneity HLOD score of 2.99 and an NPL score of 3.32. The increased scores in the restricted sample indicates that this sample is more genetically homogeneous, which could therefore increase the likelihood of positional cloning of susceptibility loci. We are repeating this study and carrying out association studies with candidate genes in the linked region.
|Number of pages||1|
|Journal||American Journal of Medical Genetics, Part B: Neuropsychiatric Genetics|
|State||Published - 8 Oct 2001|