Bardet-Biedl syndrome: a rare cause of end-stage kidney disease. Case report.

Introduction: Bardet-Biedl syndrome (BBS) is a rare autosomal recessive disorder. Diagnosis can be established with specific symptom criteria, confirmed by genetic testing. Early detection and monitoring are crucial due to the high risk of serious organ damage in affected children. We report a case of BBS at younger age admitted to our training program for severe renal failure. Our case is the first reported observation in our country, which will contribute to scientific research in Morocco and in Africa. Case presentation: An 18-year old female born to consanguineous parents, with a history of psychomotor and reduced visual acuity. She was admitted for severe kidney disease with GFR of 5 mL/min. On clinical examination, the patient was obese, polydactyly, a dysmorphic facial appearance. The fundoscopy showed a pigmentary retinopathy and pigmentary dystrophy in both eyes. Clinical discussion: BBS is a rare genetic disorder marked by features like retinal dystrophy, obesity, polydactyly, and kidney abnormalities due to defective ciliary function. Mutations in over 21 genes are linked to the disease, with some causing more severe renal outcomes. Diagnosis is based on clinical criteria and genetic testing. Management is supportive, with renal care including dialysis or transplantation when needed. Conclusion: BBS is a multisystem disorder classified as a non-motile ciliopathy due to defects in cellular organelles (cilia), which explains its diverse clinical manifestations. The frequency of CKD secondary to BBS is variable. The particularity of our case is that BBS is a very rare cause of chronic renal failure in our practical field. It has been reported in various series that diabetic and hypertensive nephropathies are the most commonly identified, rather than genetic disorders.