Epidemiological and genetic studies of congenital profound deafness in the general population of Sichuan, China.

People with congenital profound deafness (CPD) were surveyed in the general population of Sichuan. The prevalence was 0.082% (104/126, 876) of the general population, male 0.086%, female 0.078%. There was no significant difference in prevalence between urban and rural populations. However the population living in the mountains had a much higher prevalence than people from the foothills and plains (P < 0.05). Amongst the nationalities investigated, there were significant differences in prevalence. Non-Chinese, except for Tibetans, presented a significantly higher prevalence than Han Chinese. There was a significantly higher prevalence among the inbred population (0.82%) than among the non-inbred population (0.72%). An effect of parental age was demonstrated, but no effect of birth order was found. There was a significant seasonal variation in prevalence. Inherited cases could account for 71.2% of all cases, of which 92% were autosomal recessive (AR) and 8% autosomal dominant (AD). Heterogeneity in AR was found with at least 8 different loci. The fitness was 60.26%, the coefficient of selection was 0.3974, mutation rate was estimated to be 2.0 x 10(-4), and no heterozygote advantage was proven.