Abstract
We have devised nomograms relating the baseline and ACTH stimulable levels of 17-OHP, Δ 4-androstenedione and testosterone for genotyping 21-hydroxylase deficiency. The nomograms provide a method for classifying the patient with congenital, late onset or cryptic 21-hydroxylase deficiency as well as classifying the heterozygotes for each of these disorders. In addition, the subject predicted by HLA genotyping to be genetically unaffected can also be classified by these nomograms. Further the nomograms permit us to obtain evidence for genetic recombination between HLA and the 21-hydroxylase locus. For example a patient predicted by initial HLA genotyping to be unaffected was classified by the nomogram to be a heterozygote. When HLA-DR typing was performed an informative maternal HLA A:DR recombination was discovered. This recombination explained the heterozygote response of this subject. In another family a maternal DR:GLO recombination was found in an asymptomatic sister who was HLA identical to the patient with late onset 21-hydroxylase deficiency. Although most recombinants have mapped the gene for 21-hydroxylase between B and DR, this DR:GLO recombination presents evidence that there may also be a 21-hydroxylase locus between the DR-GLO loci. The nomograms thus provide a powerful tool to determine the 21-hydroxylase genotype by hormonal testing and assist in mapping the gene for 21-hydroxylase deficiency.
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New, M., Kohn, B., Pollack, M. et al. Genotyping for 21-hydroxylase deficiency: one or two genes?. Pediatr Res 15, 1558 (1981). https://doi.org/10.1203/00006450-198112000-00140
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DOI: https://doi.org/10.1203/00006450-198112000-00140