BACKGROUND: To study the association between the 21-hydroxylase deficiency with the HLA histocompatibility complex in a mediterranean ethnic group. METHODS: 5 patients with late-onset 21-hydroxylase deficiency, diagnosed on the basis of a high plasma level of 17-hydroxyprogesterone, along with 23 family members were typed. 17-hydroxyprogesterone response to iv ACTH stimulus was measured too in the family members. RESULTS: We found a genetic linkage disequilibrium between the late-onset 21-hydroxylase deficiency and the HLA antigen B51. Moreover, similar biologic profiles were observed in the patients and those of their siblings who were HLA identical. The heterozygous carriers showed a intermediate 17-hydroxyprogesterone response to ACTH between propositus and homozygotes and their family members who had no HLA haplotype identical to those of the propositus. CONCLUSIONS: These observations tend to confirm that a close linkage exits between the gene (or genes) for 21-hydroxylase deficiency in late-onset adrenal hyperplasia and the HLA genes. This association may change in the different ethnic groups.
BACKGROUND: To study the association between the 21-hydroxylase deficiency with the HLA histocompatibility complex in a mediterranean ethnic group. METHODS: 5 patients with late-onset 21-hydroxylase deficiency, diagnosed on the basis of a high plasma level of 17-hydroxyprogesterone, along with 23 family members were typed. 17-hydroxyprogesterone response to iv ACTH stimulus was measured too in the family members. RESULTS: We found a genetic linkage disequilibrium between the late-onset 21-hydroxylase deficiency and the HLA antigen B51. Moreover, similar biologic profiles were observed in the patients and those of their siblings who were HLA identical. The heterozygous carriers showed a intermediate 17-hydroxyprogesterone response to ACTH between propositus and homozygotes and their family members who had no HLA haplotype identical to those of the propositus. CONCLUSIONS: These observations tend to confirm that a close linkage exits between the gene (or genes) for 21-hydroxylase deficiency in late-onset adrenal hyperplasia and the HLA genes. This association may change in the different ethnic groups.