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

Abstract

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 CAPN10variant. Conclusion(s): The C allele at the UCSNP45 locus in CAPN10 is associated with idiopathic hirsutism, and UCSNP43 influences the hirsutism score.