Genetic mapping of the 21-hydroxylase-deficiency gene within the HLA linkage group.

To document further the proposed genetic linkage between congenital adrenal hyperplasia due to 21-hydroxylase deficiency and HLA, 34 unrelated families from New York and Zurich, with a total of 48 patients, 48 siblings and their parents, were studied. All patients were HLA genotypically different from the healthy sibs; when two or more children were affected in the same sibship they were always HLA-B identical. The gene for 21-hydroxylase deficiency was separated by genetic recombination from the HLA-A locus and from the locus for glyoxalase I-polymorphism. No HLA-A, HLA-B or HLA-C antigen was selectively increased among the 34 unrelated patients. Lod-score analysis for HLA-B:21-hydroxylase deficiency gave a peak for theta approximately 0.00 at 5.20 for females and 4.30 for males, giving a total peak lod score of 9.5 at theta approximately 0.00 when male and female lod scores were combined. Close genetic linkage between HLA-B and 21-hydroxylase deficiency was thus established.