Introduction

Polycystic ovary syndrome (PCOS) is the most common endocrine problem affecting women of reproductive age and is reported from many regions of the world. Some reports indicate ethnic differences in its manifestation. This chapter examines the evidence for ethnic variation in the PCOS phenotype and explores the possible basis of this phenomenon.

Despite having a relatively recent ancestry, the species of modern Homo sapiens sapiens is a non-homogeneous group, as is evident from their differing physical, behavioural and social characteristics. Such variation has the potential to affect the prevalence and presentation of common diseases. Every human being has a unique inherited (genetic) make-up that can be affected by many environmental (non-genetic) influences during life that can modify external features and manifestations. Spielman et al. demonstrated that the expression of some genes differs significantly among different ethnic groups. Phenotypic variations in human populations may be caused by natural selection and adaptation to environmental conditions. Recent genome-wide studies have identified a few loci that contribute to differentiation of disease-related phenotypic diversity.

Researchers studying PCOS in depth need to decipher any ethnic variations of its genotype and phenotype. This requires sound epidemiological evidence that can characterise risks, both at an individual and a population level, to enable effective planning of prevention and treatment strategies. Such an analysis must also consider variations in normal traits, risk factors for comorbidities, response to treatment and effects of pharmacological agents.