Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a heterogenous condition which disturbs endocrine, metabolic and reproductive function, affecting 6-10% of women of reproductive age. Such a disorder can be defined using the Rotterdam criteria of 2003, which states PCOS is present when two of the following three phenotypes is shown: polycystic ovaries, hyperandrogenism and ovulatory dysfunction. However in recent years, PCOS has been found to present several metabolic consequences such as insulin resistance (affecting 60-80% of women with PCOS), hyperinsulinaemia, type 2 diabetes mellitus and dyslipedemia; a dangerous combination which poses major risk factors in the development of cardiovascular disease (CVD). Obesity in particular has been linked to inflammation

Similarities of PCOS phenotypes across families supports the importance of environmental factors as contributors in the manifestation of the condition. Such factors may include diet, particularly the consumption of carbohydrates and fats, lack of exercise and smoking. Socioeconomic status may also play a role as correlations between children who come from families of low socioeconomic status and PCOS were found (Barthelmess & Naz, 2015). Prenatal life is also of interest as an environmental risk factor, a study by Cresswell et al., 1997 found two different groups of patients who both displayed the PCOS phenotype: those with birth weights above average and those who were born to overweight mothers (Crosignani & Nicolosi, 2001). Additionally, PCOS is not geographically restricted, affecting women of reproductive age worldwide. Ethnicity studies reinforce the variation in the expression of PCOS phenotypes, mainly with focus on the metabolic aspects of the syndrome. Examples include the high prevalence of obesity among Hispanic and African American women, putting them at a higher risk of developing type 2 diabetes mellitus; abnormal glucose tolerance is also more common in these populations of women than when compared to European women. Asian women tend to have lower body mass index (BMI) and hyperandrogenism which is less severe compared to

The study carried out identified three loci linked to PCOS in a Chinese cohort. The first locus concerning PCOS was found on chromosome 2p16.3, containing two genes GTF2A1L (expressed in the testis) and LHCGR essential for ovulation and pregnancy. The THADA gene was also discovered, expressed on chromosome 2p21and the third and final susceptible locus was found on chromosome 9q33.3 in DENND1A, a gene important in membrane trafficking (Barthelmess & Naz, 2015).