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What is polycystic ovary syndrome and how does it affect fertility? – Causes, symptoms, treatment and genetic testing

Medicover Genetics Editorial Team |
December 14th 2022

Healthcare systems around the world should be encouraged to make polycystic ovary syndrome a priority in women’s health checks. Polycystic ovary syndrome (PCOS) affects 1 in 10 women worldwide and it is one of the most common reasons for impaired fertility in women. PCOS affects the female reproductive system by causing the ovaries to produce an abnormal amount of androgen, a group of hormones responsible for the growth and reproduction of women and men. Women produce only a small amount of androgens, which is why they are considered male hormones. A hormonal imbalance causes ovulation failure, which prevents the small egg follicles from growing, resulting in cyst formation. The name PCOS refers to the accumulation of multiple small cysts in the ovaries that characterizes the disease.

The first known case of PCOS was observed in 1721, but formal diagnostic criteria were not set until the early 1990s. In 2010, the World Health Organization estimated that PCOS affects 116 million women worldwide. Despite its high prevalence, the exact causes of the syndrome are still not fully understood.

What causes polycystic ovary syndrome?

PCOS is a multifactorial disease, as it is caused by genetic, hormonal, and environmental factors such as hereditary genetic changes, insulin resistance, increased levels of inflammation, stress, poor diet, nutrition, and environmental toxins.

What are the symptoms of polycystic ovary syndrome?

The first symptoms of PCOS start appearing around puberty, at the time of the first menstrual period. The most common symptoms include

  • Irregular periods, i.e., inconsistent, absent, heavy, or painful periods
  • Excess body hair
  • Acne
  • Headaches
  • Weight gain

The majority of the symptoms are a result of hormone imbalance and higher levels of androgens. More than half of the women with PCOS experience no symptoms, apart from difficulty in conceiving. PCOS related weight gain is associated with an increased risk of type 2 diabetes, high cholesterol, impaired glucose tolerance, cardiovascular diseases, and hypertension. PCOS also increases the risk of endometrial carcinoma.

Polycystic ovary syndrome vs polycystic ovaries

PCOS is frequently mistaken for polycystic ovaries (PCO), which is a very common condition occurring in almost one-third of women of reproductive age. Even though these are related conditions with shared symptoms, such as irregular periods, acne, and weight gain, PCO refers to normal ovaries with multiple follicles and is not considered a disorder, while PCOS is a metabolic disorder associated with hormonal imbalance. PCOS and PCO also vary in associated risks, incidence, and clinical management, with PCOS being more severe than PCO. In addition, PCO can be diagnosed with an ultrasound, whereas the diagnosis of PCOS requires additional blood tests to check hormone levels.

Genetics of polycystic ovary syndrome

Familial clustering and twin studies suggest that PCOS has a genetic component. Indeed, as more and more studies research the genes associated with PCOS, it becomes clear that it is a polygenic disorder due to the involvement of multiple genes. An estimated 241 genes and 114 single nucleotide polymorphisms (SNP) are associated with PCOS, as reported in 2016.

Research has focused on genes involved in the production of reproductive hormones as their levels are altered in PCOS.

  • Genes involved in ovarian and adrenal hormone production (CYP11a, CYP21, CYP17 and CYP19) are logical targets for study and variants are associated with PCOS. Variants in these genes mean that androgen cannot be converted into estrogen resulting in raised androgen levels.
  • Variants in the androgen receptor (AR) gene that is located on the X chromosome have been reported in PCOS. Gene inactivation disrupts the androgen-signaling pathway resulting in elevated androgen levels.
  • Variants in the follicular stimulating hormone receptor (FSHR) gene upset the levels of follicular stimulating hormone, which impacts the severity of PCOS.
  • SNP in the sex hormone-binding globulin gene (SHBG) has been reported in PCOS. Variants in this gene affect the level of sex hormones.
  • Polymorphisms in the luteinizing hormone (LH) β-subunit gene affect the level and function of LH and have been reported in PCOS.
  • Variants in the AMH gene, which is involved in infertility, are also associated with PCOS.

Genes involved in the secretion and action of insulin and insulin resistance (such as IRS-1, IRS-2 and CAPN10) and other genes, including the fat mass obesity (FTO) gene, PCOS1, SRD5A2 and SRD5A1, have also been research targets.

Epigenetic changes are also important in the etiology of PCOS. These are changes that alter how the body reads a DNA sequence, but do not alter the DNA sequence itself. The epigenetic inheritance of PCOS-like traits has been demonstrated in mice and may also be applicable in humans.

Genetic testing for polycystic ovary syndrome

Genetic testing can be performed to identify any changes in the genes known to be associated with PCOS, and consequently help with improving the classification of the syndrome and its phenotypes, as well as allowing for early interventions to reduce the PCOS-associated risks.

How to treat polycystic ovary syndrome?

Although there is no cure for PCOS, the symptoms are manageable and treatable. Treatment will depend on various factors, such as the woman’s age and her exact symptoms, and whether she plans to become pregnant. Infertility treatment starts with lifestyle modifications, such as implementing a healthier diet and becoming more physically active. Even a minor weight loss can help improve the body’s ability to regulate insulin and subsequently improve ovulation. It can also help increase the efficacy of any other medication, such as ovulation induction drugs to help the ovaries release eggs. For women not planning a pregnancy in the immediate future, birth control pills can decrease androgen levels and treat various symptoms, such as irregular menstruation, excessive hair growth, and acne. Diabetes medication can be used to treat high insulin resistance.

Conclusion

Polycystic ovary syndrome is one of the most common causes of impaired fertility in women, and PCOS related weight-gain can increase the risk of other serious diseases, such as type 2 diabetes and hypertension. Increasing awareness about PCOS can promote the need for timely diagnosis and improve treatment and prognosis for affected women. Governments and healthcare systems around the world should be encouraged to make PCOS a priority in women’s health checks, understand the struggles and improve the quality of life for women and girls with PCOS.

Please note: The content of this article is for informational purposes and is not intended to replace medical advice. Please visit your healthcare provider if you have concerns about your health and well-being.

References

[1] Deswal R et al. The Prevalence of Polycystic Ovary Syndrome: A Brief Systematic Review. J Hum Reprod Sci2020 Oct-Dec;13(4):261-271. doi: 10.4103/jhrs.JHRS_95_18. Epub 2020 Dec 28. PMID: 33627974; PMCID: PMC7879843. https://doi.org/10.4103/jhrs.JHRS_95_18

[2] Prapas N et al. Genetics of polycystic ovary syndrome. Hippokratia. 2009 Oct;13(4):216-23. PMID: 20011085; PMCID: PMC2776334. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2776334/

[3] Johns Hopkins Medicine. Polycystic Ovary Syndrome (PCOS). Retrieved September 2021 from https://www.hopkinsmedicine.org/health/conditions-and-diseases/polycystic-ovary-syndrome-pcos

[4] Mayo Clinic. Polycystic ovary syndrome (PCOS) – Symptoms & causes. Retrieved September 2021 from https://www.mayoclinic.org/diseases-conditions/pcos/symptoms-causes/syc-20353439

[5] NHS. Polycystic ovary syndrome. Retrieved September 2021 from https://www.nhs.uk/conditions/polycystic-ovary-syndrome-pcos/

[6] WebMD. Polycystic Ovary Syndrome (PCOS). Retrieved September 2021 from https://www.webmd.com/women/what-is-pcos

[7] Office on Women’s Health. Polycystic ovary syndrome. Retrieved September 2021 from https://www.womenshealth.gov/a-z-topics/polycystic-ovary-syndrome

[8] Joseph S et al PCOSKB: A Knowledge Base on genes, diseases, ontology terms and biochemical pathways associated with PolyCystic Ovary Syndrome. Nucleic Acids Res Volume 44, Issue D1, 4 January 2016, Pages D1032–D1035 https://doi.org/10.1093/nar/gkv1146

[9] Khan MJ et al. Genetic Basis of Polycystic Ovary Syndrome (PCOS): Current Perspectives. Appl Clin Genet 2019 Dec 24;12:249-260. doi: 10.2147/TACG.S200341. PMID: 31920361; PMCID: PMC6935309. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6935309/pdf/tacg-12-249.pdf

[10] Nida Ajmal et al Polycystic ovary syndrome (PCOS) and genetic predisposition: A review article. European Journal of Obstetrics & Gynecology and Reproductive Biology: X, Volume 3, 2019, 100060, ISSN 2590-1613, https://doi.org/10.1016/j.eurox.2019.100060. https://www.sciencedirect.com/science/article/pii/S2590161319300948

[11] Zimmer K. Polycystic Ovary Syndrome May Be Inherited Epigenetically. Retrieved December 2022 from https://www.the-scientist.com/news-opinion/polycystic-ovary-syndrome-may-be-inherited-epigenetically–68434

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