SAT-132 - Not Grown Up Yet; A Case Report of Bardet-Biedl Syndrome with Amenorrhea and Gonadal Dysfunction

Background:
Bardet–Biedl syndrome (BBS) is a rare multisystem autosomal recessive ciliopathy characterized by rod–cone dystrophy, renal abnormalities, postaxial polydactyly, learning difficulties, central obesity, and hypogonadism. In addition to these primary features, endocrine manifestations, particularly abnormalities of pubertal development and reproductive function, are common but frequently under recognized. Diagnosis is based on clinical features and may be confirmed by genetic testing. We report a case of genetically confirmed BBS10-related Bardet–Biedl syndrome presenting with primary amenorrhea and metabolic complications, highlighting the importance of early and comprehensive endocrine evaluation.

Case Presentation:
A 19-year-old female presented for evaluation of primary amenorrhea. She had a prior clinical diagnosis of Bardet–Biedl syndrome, confirmed by genetic testing demonstrating compound heterozygous pathogenic variants in the BBS10 gene. She exhibited multiple cardinal features of BBS, including central obesity (BMI 30 kg/m²), surgically corrected postaxial polydactyly, progressive visual impairment due to retinal dystrophy, learning difficulties, mild renal dysfunction, and recurrent otitis media requiring tympanostomy tube placement and was recently diagnosed with type 2 diabetes mellitus.

Gynecologic history revealed absence of menarche without cyclic pelvic pain, galactorrhea, or clinical hyperandrogenism. A progesterone withdrawal challenge was negative. Hormonal evaluation demonstrated low estradiol levels with inappropriately normal follicle-stimulating hormone and luteinizing hormone concentrations, suggesting a mixed pattern of gonadal dysfunction and central hypogonadism. Free testosterone was mildly elevated; pituitary and thyroid hormone levels were within normal limits. Pelvic ultrasound revealed a thin endometrial stripe without ovarian enlargement or cystic morphology.

Conclusion:
Hypogonadism is a common but heterogeneous endocrine feature of Bardet–Biedl syndrome (BBS), reflecting combined hypothalamic–pituitary and primary gonadal dysfunction. This patient’s profile supports a mixed mechanism for primary amenorrhea. BBS10 accounts for ~20% of genetically confirmed cases and is often linked to severe obesity and type 2 diabetes. Early recognition is essential to prevent long-term reproductive, skeletal, and metabolic complications.

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