OBJECTIVETo study the clinical characteristics and diagnostic methods of rare autosomal recessive inherited Bardet-Biedl syndrome in patients presented with renal abnormalities.

METHODComprehensive analyses were performed on data of 4 confirmed Bardet-Biedl syndrome cases seen at nephrology department of Beijing Children Hospital affiliated to Capital Medical University, including clinical features, laboratory examination and diagnostic criteria.

RESULT(1) Four cases were confirmed to meet Bardet-Biedl syndrome diagnostic criteria (male: female = 1: 1): first diagnosis age was 10 y, 9 y 8 m, 10 y 10 m, 8 y 2 m. (2) Cases 1, 2, and 3 had a history of polyuria and polydipsia, cases 4 began with edema and oliguria. (3) All had slight change in urine routine test. Case 3 and Case 4 were presented with small to medium amount of proteinuria. None had microscopic hematuria. (4) All had different degree of renal injury, Case 1 and 3 were at the third phase of chronic kidney disease (CKD), Case 4 was at the fourth phase of CKD, Case 4 was at the fifth phase of CKD and needed dialysis. (5) All cases had obvious abnormalities of urinary tract ultrasound, 3 of them had chronic diffuse lesions with cyst formation of both kidneys. The rest one had dysplasia of right kidney and fused kidney. (6) All cases were presented with vision loss with 100% of electroretinogram abnormalities and 50% of fundus examination abnormalities. (7) Three cases were presented with obesity. (8) Multiple organs were involved in all cases, including electrocardiographic abnormality and/or thickening of the left ventricular wall (4/4) , polydactyly (2/4) , small penis and testicles (2/4) and short stature (2/4) .

CONCLUSIONClinical manifestations of Bardet-Biedl syndrome (BBS) conceals, routine urine test changes slightly, abnormalities of renal structure and (or) tubular interstitial function is a typical manifestation of children with BBS. Urinary tract ultrasound screening may show diffuse lesions with double kidney with cyst formation or structural abnormalities. Clinical manifestation accompany with retinal degeneration, obesity, myocardial involvement, polydactyly, and hypogonadism.