Prevalence and genetic aspects of deaf mutism in Shanghai.

Two hundred and eighty-five cases of congenital deaf mutism were ascertained in a population of 483,611 in Zhabei District in Shanghai. The prevalence was 0.059% (1:1697). Inherited cases accounted for 84.83% of all cases. The mode of inheritance was autosomal recessive with complete penetrance and heterogeneity (consisting of at least five different loci). The fitness was 77.63%, the coefficient of selection was 0.2237, the mutation rate was 1.119 x 10(-4) mutation/gamete, and no heterozygote advantage was proven.