Common single nucleotide polymorphisms in intron 3 of the calpain-10 gene influence hirsutism.

OBJECTIVE: To study three common polymorphisms in intron 3 of the calpain-10 gene (CAPN10) in hyperandrogenic patients.

DESIGN: Case-control study.

SETTING: Academic hospital.

PATIENT(S): Ninety-seven hyperandrogenic patients and 37 healthy controls.

INTERVENTION(S): Basal and adrenocorticotropin-stimulated serum samples and genomic DNA samples were obtained during the follicular phase of the menstrual cycle.

MAIN OUTCOME MEASURE(S): Genotyping of the UCSNP43, UCSNP44, and UCSNP45 polymorphisms in CAPN10 and serum androgen levels.

RESULT(S): Sixteen patients had idiopathic hirsutism, defined as normal serum androgen levels and regular menstrual cycles. Eighty-one hyperandrogenic patients (those presenting with hyperandrogenemic hirsutism or the polycystic ovary syndrome) were analyzed further. UCSNP45 alleles were distributed differently among the study groups. Heterozygosity for the uncommon C allele was increased in patients with idiopathic hirsutism (31.3%) and reduced in hyperandrogenic patients (7.4%) compared with controls (16.2%). The UCSNP44 and UCSNP43 alleles were in linkage disequilibrium, and were distributed equally among patients with idiopathic hirsutism, hyperandrogenism, and controls. However, the uncommon A allele at UCSNP43 was associated with higher hirsutism score (mean [+/- SD], 9.9 +/- 6.8, 12.7 +/- 7.7, and 14.6 +/- 8.2 in GG, GA, and AA participants, respectively). No other differences were observed in clinical and biochemical characteristics, including insulin sensitivity, by CAPN10 variant.

CONCLUSION(S): The C allele at the UCSNP45 locus in CAPN10 is associated with idiopathic hirsutism, and UCSNP43 influences the hirsutism score.