Abstract

Leptin and leptin receptor gene polymorphisms in polycystic ovary syndrome

Author(s): R.Suganthi, J.Fathima Benazir

Polycystic ovary syndrome (PCOS) is a heterogeneous disorder affecting female infertility originally described as early as 1935.Genetic studies have identified a link between PCOS and disordered insulin metabolism, and indicate that the syndrome may be the presentation of a complex genetic trait disorder. Leptin is also important in regulating the onset of puberty. Extremely thin women often stop ovulating and abnormally thin adolescent women enter puberty later than their heavier counter parts, indicating that fat tissue may produce a signal that regulates reproduction, this factor may be leptin. Treatment of mice with leptin accelerates the maturation of the female reproductive tract and leads to an earlier onset of the estrous cycle and reproductive capacity. Serum leptin concentration in women with PCOS has been reported to be higher than or similar to those in weight-matched controls.Mutations of the LEP gene lead to obesity in ob/ obmice. In the present study,LEP (-2548)G/Aand LEPRQ223Rgenotypes in a series of PCOS cases and normal controls were analyzed. The prevalence of the alleleswas different in the 2 groups, control and PCOSwomen. For the LEP (-2548) G/A, the overall distribution of the 3 genotypes in the PCOS patients (GG 19%; GA 56%; AA 25%) was comparable with the distributions found in related subjects of normal control (GG 28%; GA 50%;AA22%). Exonic polymorphisms in the LEPR gene, namelyQ223R polymorphism on the leptin concentration variable in a selected population of PCOS patients and normal control were studied. These polymorphisms cause a change in charge (Glutamine[Q] to Arginine[R]) at codon 223. For the Q223R polymorphism, the overall distribution of the 3 genotypes in the PCOS patients (QQ 45%; QR 41%; RR 14%) were compared with the distribution found in related subjects of normal control (QQ 40%; QR 57 %; RR 3%). Findings suggest that, in this sample, regulatory sequence primarily predisposing to early onset obesity was not in close linkage equilibriumwith these polymorphisms.