ABSTRACT
INTRODUCTION: Polycystic Ovary Syndrome (PCOS) is a complex endocrine disorder, of multifactorial etiology, which affects 6-10% of women of reproductive age. It is considered the leading cause of anovulatory infertility, menstrual disorders and hyperandrogenism in this population. The genetic basis of PCOS is still largely unknown despite significant family clustering; determining its mode of inheritance is particularly difficult given the heterogenic presentation of the disease. MATERIALS AND METHODS: 130 Brazilian women, aged 14-42 years, who met the 2003 Rotterdam criteria for PCOS diagnosis, were included, and 96 healthy women constituted the control group. Presence of hirsutism was classified using the modified Ferriman-Gallwey score (F-G score) as absent (≤7), mild (8-14), and severe (≥15). Blood levels of luteinizing hormone (LH), total testosterone (TT), dehydroepiandrosterone sulfate (DHEA-S) and androstenedione were determined. The coding region of the luteinizing hormone beta-subunit (LHB) gene was amplified and sequenced. Differences in allelic and genotypic frequency distribution of each polymorphism across controls and cases were estimated by the Mantel-Haenszel chi-square or Fisher's exact test (p<0.05), and the probability of an association between the detection of a polymorphism and presence of a diagnosis of PCOS, by logistic regression. RESULT(S): Sequencing detected 8 polymorphisms in the LHB gene coding region. Two polymorphisms in linkage disequilibrium were significantly more prevalent in the presence of hyperandrogenemia: rs1800447/rs34349826 (Trp28Arg/Ile35Thr) (p=0.02). CONCLUSION(S): In this series, a modulatory effect of LHB polymorphisms on hyperandrogenemia phenotype of PCOS was observed; however, this finding needs to be replicated in other populations.
Subject(s)
Luteinizing Hormone, beta Subunit/genetics , Polycystic Ovary Syndrome/blood , Polycystic Ovary Syndrome/genetics , Polymorphism, Single Nucleotide , Testosterone/blood , Adolescent , Adult , Amino Acid Substitution , Androstenedione/blood , Brazil , Dehydroepiandrosterone Sulfate/blood , Female , Gene Frequency , Genotype , Humans , Linkage Disequilibrium , Luteinizing Hormone, beta Subunit/blood , Young AdultABSTRACT
Selective luteinizing hormone deficiency due to mutations in the luteinizing hormone beta-subunit gene (LHB) is a rare cause of hypogonadism. We describe the clinical features of a consanguineous family in which three siblings, two men and one woman, had hypogonadism related to isolated luteinizing hormone deficiency. These subjects have a newly discovered homozygous mutation of a 5' splice site in LHB: IVS2+1G-->C. This mutation disrupts the splicing of messenger RNA (mRNA), generating a gross abnormality in the processing of the luteinizing hormone beta-subunit mRNA, which abrogates the secretion of luteinizing hormone. We also determined that the female phenotype of this LHB mutation is characterized by normal pubertal development, secondary amenorrhea, and infertility.
