Species: human
Mutation name: None
type: naturally occurring
fertility: fertile
Comment: FTO and MC4R Gene Variants Are Associated with Obesity in Polycystic Ovary Syndrome. Ewens KG et al. Polycystic ovary syndrome (PCOS) is the leading cause of anovulatory infertility in women. It is also associated with metabolic disturbances that place women at increased risk for obesity and type 2 diabetes. There is strong evidence for familial clustering of PCOS and a genetic predisposition. However, the gene(s) responsible for the PCOS phenotypes have not been elucidated. This two-phase family-based and case-control genetic study was designed to address the question of whether SNPs identified as susceptibility loci for obesity in genome-wide association studies (GWAS) are also associated with PCOS and elevated BMI. Members of 439 families having at least one offspring with PCOS were genotyped for 15 SNPs previously shown to be associated with obesity. Linkage and association with PCOS was assessed using the transmission/disequilibrium test (TDT). These SNPs were also analyzed in an independent case-control study involving 395 women with PCOS and 176 healthy women with regular menstrual cycles. Only one of these 15 SNPs (rs2815752 in NEGR1) was found to have a nominally significant association with PCOS (?(2)?=?6.11, P?=?0.013), but this association failed to replicate in the case-control study. While not associated with PCOS itself, five SNPs in FTO and two in MC4R were associated with BMI as assessed with a quantitative-TDT analysis, several of which replicated association with BMI in the case-control cohort. These findings demonstrate that certain SNPs associated with obesity contribute to elevated BMI in PCOS, but do not appear to play a major role in PCOS per se. These findings support the notion that PCOS phenotypes are a consequence of an oligogenic/polygenic mechanism.

Species: human
Mutation name:
type: naturally occurring
fertility: subfertile
Comment: MC4R variants rs12970134 and rs17782313 are associated with obese polycystic ovary syndrome patients in the Western region of Saudi Arabia. Batarfi AA et al. (2019) Polycystic ovary syndrome (PCOS) is a common endocrine disorder causing infertility in reproductive-age women. The cause of PCOS is not fully understood but it is thought to be influenced by environmental and genetic factors. Obesity is greatly related to PCOS and its reduction is one of the major aims in treating PCOS. Melanocortin 4 receptor (MC4R) gene polymorphisms were detected to be associated with different levels of obesity. Therefore, we aimed to determine the genotype and allele frequency of MC4R variants rs12970134 (A/G) and rs17782313 (C/T) in PCOS and investigate their association with PCOS and its clinical variables. A case-control study was conducted on 189 women, consisting of 95 PCOS cases and 94 controls. Genotyping was performed by real-time polymerase chain reaction (PCR) using TaqMan™ Genotyping assays. Quantitative data were presented as (median ± interquartile range (IQR) whereas qualitative data were presented as frequencies. The chi-squared test was used to observe the difference between SNPs within the study groups (PCOS and control subjects). Multinomial logistic regression was used to test the risk of obesity and development of PCOS considering p < 0.05 is statistically significant. Rs12970134 and rs17782313 are significantly associated with body mass index (BMI, kg/m², p < 0.0001) in PCOS women but not associated with PCOS itself. Risk alleles in our population are A in rs12970134 and C in rs17782313 that are associated with high BMI (> 30 kg/m²) in obese women with PCOS (OR = 1.348, p = 0.002 and OR = 1.364, p = 0.002 respectively) in the homozygous state. In addition, we found that the other genotypes for non-obese PCOS group, AG/GG for rs12970134 and CT/TT for rs17782313, are associated with hirsutism, loss of hair, hyperandrogenism and anti-Müllerian hormone in PCOS. These findings demonstrate that MC4R single nucleotide polymorphisms, rs12970134 and rs17782313, are correlated with elevated BMI in PCOS but are not causative factors for PCOS among women in the western region of Saudi Arabia. Moreover, the reverse genotypes are associated with major clinical variants in non-obese (< 30 kg/m²) PCOS patients may demonstrate a poor prognosis for this group.//////////////////