An uncommon cause of severe polycystic ovary syndrome (PCOS)

IntroductionPolycystic ovaries in adolescent girls with irregular periods are most commonly associated with insulin resistance and hypergonadism within the PCOS. In rare instances, these findings may be caused by other underlying disorders (1,2).Case presentationA 16-year-old girl was admitted to the endocrinology department due to polyuria, polydipsia, and weight loss. Irregular periods presented at the age of 12, and hirsutism since 14 years of age. Clinical examination revealed hirsutism (Ferriman-Gallwey score 22), and severe acanthosis nigricans. BMI and fat mass distribution were normal. Baseline investigations revealed elevated glucose levels (6.9 mmol/L), elevated HbA1c (7.8%), and glycosuria.Further investigation showed impaired glucose tolerance with insulin levels up to 488 mIU/L, HOMA-IR of 41, high levels of testosterone (4.6 nmol/L), androstenedione, DHEAS, and anti-Mullerian hormone (75.3 ng/ml). Antibodies usually present in type 1 diabetes mellitus (T1DM): GAD and IA2, TPO, as well as ANA antibodies, were negative. Pelvic ultrasound detected polycystic ovaries.Because severe insulin resistance and hyperandrogenism are uncommon in adolescents with normal BMI, molecular genetic testing was conducted. Heterozygous likely pathogenic deletion of exons 15 to 22 in the INSR gene was detected, confirming the diagnosis of Type A insulin resistance syndrome.Oral metformin therapy and oral contraceptive pills were introduced.ConclusionMisdiagnosis is likely when severe insulin resistance is covered up by other signs or symptoms of Type A insulin resistance syndrome, such as PCOS.Written informed consent for the anonymized use of medical information for the purposes of writing and publishing a case report has been obtained from both the girl and her parents.