Bardet-Biedl syndrome with unique manifestations of congenital giant nevi and refractory anemia: a case report from Palestine.

Introduction and importance: Bardet-Biedl syndrome (BBS) is a rare autosomal recessive disorder impacting multiple organs. Characterized by renal dysfunction, retinal dystrophy, obesity, polydactyly, intellectual disability, and hypogonadism, it lacks targeted treatment. Diagnosis relies on clinical criteria, and management emphasizes early detection, complication screening, and genetic counselling. Case presentation: A 4-year-old boy, born to first-cousin parents, presented with refractory iron-deficiency anaemia (IDA) and recurrent respiratory infections. Prenatal ultrasound revealed renal and limb anomalies. Physical examination showed dysmorphic features, polydactyly, and a giant-congenital naevus. Genetic testing revealed a homozygous MKKS variant. Despite oral iron, severe IDA persisted. Intravenous iron therapy yielded significant improvement. Clinical discussion: BBS, an autosomal recessive ciliopathy, involves various genes. In this case, the MKKS gene variant contributed to the syndrome. The incidence of BBS in the Arab population is discussed, emphasizing its rarity and varied clinical presentations. Incidence in the Arab population, including Palestine, is 1 in 13 500. Diagnostic criteria, encompassing major and minor features, highlight BBS complexity. Renal anomalies, visual disturbances, and cutaneous manifestations are common. Multidisciplinary care addresses systemic involvement with emerging treatments like setmelanotide. Conclusion: This case underscores BBS's rarity and complexity, featuring unique aspects like giant nevi and refractory IDA. Comprehensive management addresses renal, visual, cardiac, and neurologic aspects. Genetic counselling, prenatal testing, and preimplantation genetic diagnosis prevent transmission. Limitations include lacking local epidemiological data and prior studies in Palestine. This case contributes insights, stressing multidisciplinary management and prompting further research in underexplored populations.