Exp Clin Endocrinol Diabetes 2005; 113 - V3_29
DOI: 10.1055/s-2005-862813

17α-Hydroxylase/17,20-lyase deficiency caused by homozygosity of a novel mutation (Y27Stop) in the cytochrome P450c17 (CYP17) gene

K Müssig 1, S Kaltenbach 1, G Schnauder 1, C Maser-Gluth 2, F Machicao 1, HU Häring 1, B Gallwitz 1, FJ Seif 1
  • 1Universitätsklinikum Tübingen, Medizinische Klinik IV, Tübingen
  • 2Universität Heidelberg, Steroidlabor des Pharmakologisches Institutes, Heidelberg

Objective: We report on a rare case of 17α-hydroxylase/17,20-lyase deficiency caused by homocygosity of a novel mutation of the cytochrome P450c17 (CYP17) gene.

Case report: A 20-year old female Turkish patient (46, XX), phenotypically female, presented with primary amenorrhea, sexual infantilism, and easy fatiguability. Hormonal data showed low or undetectable plasma concentrations of 17α-hydroxycorticoids, androgens, and estrogens, while ACTH, FSH, and LH levels were elevated. The plasma levels of the mineralocorticoid precursors were increased, whereas aldosterone concentration was within the lower normal range and the plasma renin activity was decreased. The hormonal findings are consistent with combined 17α-hydroxylase/17,20-lyase deficiency and therapy with hydrocortisone and conjugated estrogens was initiated. CYP17 gene analysis revealed homocygosity of the mutation Y27Stop (TAC to TAA) in exon 1; which has not been previously described.

Conclusions: This is the first description of homocygosity of a mutation in the CYP17 gene leading to a stop codon in a patient with combined 17α-hydroxylase/17,20-lyase defiency.