Possible genetic linkage disequilibrium between HLA and the 21-hydroxylase deficiency gene (congenital adrenal hyperplasia)

Congenital adrenal hyperplasia (CAH) of the 21-hydroxylase deficiency (21-OH-def) type is due to an autosomal recessive gene that recently has been shown to be located within the HLA complex. With additional studies, the 21-OH-def gene has been separated by genetic recombination from the HLA-A locus in 3 informative families and from the locus for glyoxalase-I-polymorphism (GLO) in 2 families. It has not yet been separated by recombination from the HLA-B locus. The authors have now investigated the HLA-A, B, and C antigen frequencies in 37 unrelated white patients with CAH of the 21-OH-def type in order to determine whether the presence of this gene is associated with any particular HLA antigens. Although a few antigens and antigen combinations (haplo-types) were found to be selectively increased or decreased among the patients, a large number of different HLA-B determinants can apparently coexist with the 21-OH-def gene.