Gene mapping studies with the syndrome of autism

The UCLA Registry for Genetic Studies of Autism had collected data on 308 families by February 1, 1983. A subsample of 46 families withat least two affected children was analyzed for evidence of a Mendelian mode of inheritance. The data were consistent with an autosomal recessive mode of inheritance (Ritvo, E. R., Spence, M. A., Freeman, B. J. Mason-Brothers, A., Mo. A., and Marazita, M. L., 1985, American Journal of Psychiatry, in press). Thirty-four of these families were subjected to gene linkage analyses with 30 standard phenotypic gene markers. There is no evidence of linkage between the purported autism locus and HLA, either from analysis of HLA haplotype sharing or fromlod scores. In addition, close linkage with autism, i.e., ≤5% recombination, could be excluded for 19 of the other autosomal genetic markers. The largest positivelod score, 1.04, was with haptoglobin (HP), at recombination frequencies of 10% in males and 50% in females. Normal C-and Q-banded chromosome polymorphisms were evaluated for association with autism and as additional linkage markers.