[Congenital adrenal hyperplasia (21-OH) in France. Population genetics].

Incidence of congenital adrenal hyperplasia due to 21 hydroxylase deficiency was studied in France. Five hundred and twenty six patients born during the period 1963-1979 were found. Assuming complete ascertainment in females, the incidence of the disease is 0.43 X 10(-4) or 1: 23,044. The frequency of the carriers is 0.013 (1/76). The birth places of patients show an unequal geographic distribution. The mean inbreeding coefficient is 270 X 10(-5), a figure higher than the mean coefficient of France. The frequency of marriages between first cousins is slightly raised, 0.3%.