Bardet–biedl syndrome: A rare case with ocular and systemic manifestations

Bardet–Biedl syndrome (BBS) is an uncommon autosomal recessive ciliopathy. It presents with retinal degeneration, obesity, polydactyly, cognitive impairment, hypogonadism, and renal disease. We describe a 15-year-old boy who presented with diminution of vision in both eyes and had a long-standing night blindness. Examination showed hand-motion visual acuity in both eyes and dense bilateral posterior subcapsular cataracts. After uneventful cataract surgery vision improved to 6/60 and fundus examination revealed waxy optic disc pallor, attenuated retinal vessels, and macular atrophy suggestive retinal dystrophy. Central obesity, bilateral postaxial polydactyly of the feet, hypogonadism and mild cognitive impairment were also observed. A clinical diagnosis of Bardet–Biedl syndrome was thus made. It was supported by molecular testing, which identified a pathogenic variant of the BBS12 gene. The patient was started on low-vision rehabilitation and referred for genetic counselling and weight management. This report reviews the ocular features of BBS, discusses the diagnostic value of early cataracts and atypical pigmentary retinopathy in a child with systemic dysmorphism, and highlights the role of ophthalmologists in initiating the diagnostic pathway for this multisystem disorder.