According to current diagnostic criteria, polycystic ovary syndrome (PCOS) is effective as a diagnosis of exclusion. Here, we present a case of a 31-year-old woman with a history of oligomenorrhoea and hirsutism, who, despite a "muscular" appearance and a normal body mass index (22.27 kg/m2), was found to have an extreme insulin resistance and diabetes accompanied by hyperandrogenism and polycystic ovaries. An autoimmune screen for possible latent autoimmune diabetes in adults was negative. She was subsequently found to have familial partial lipodystrophy (FPLD2, OMIM #151660) caused by an R482Q mutation in the LMNA gene encoding lamin A/C. This mutation results in arginine to glutamine substitution at the protein level, while phenotypically this condition presents with a loss of body fat, insulin resistance, dyslipidaemia, and other features mimicking PCOS. Interestingly her mother, with a history of myocardial infarction and diabetes at the age of 46 but no oligomenorrhoea, was also found to harbour the same mutation (LMNA R482Q).
Conclusions: Our case highlights the importance of assessment of adipose tissue distribution, as well as a significance of assessment of glucose tolerance and insulin resistance in the differential diagnosis of PCOS. Furthermore, patients with atypical adipose tissue distribution should be referred for formal genetic testing.
Keywords: insulin resistance; lipodystrophy; polycystic ovary syndrome.