Late-onset type of 21-hydroxylase deficiency in childhood.

It was recently proposed that congenital and late-onset 21-hydroxylase deficiency are caused by two distinct recessive allelic genes. Although both genes are associated with the HLA system, only the late-onset type was found to be linked with the antigens B14 and DR1. Biochemical and immunological studies were conducted in two families with children suffering from 21-hydroxylase deficiency of postnatal onset. In the first family, of Jewish Ashkenazic origin, a 2 1/2-yr-old girl presenting with clitoromegaly was found to be homozygous for the antigens B14 and DR1. In the second family, of Arabic origin, all the children, their parents and a paternal aunt were clinically and/or biochemically affected, carrying the B14, but not the DR1 antigen on one or both HLA haplotypes. These data suggest that some cases of simple virilizing 21-hydroxylase deficiency in childhood are related to the late-onset type of 21-hydroxylase deficiency.