Bardet-Biedl syndrome (BBS) is an autosomal recessive multi-system disorder consisting of obesity, retinal degeneration, cognitive impairment, genitourinary tract malformations and polydactyly. Polycystic kidneys are the most likely cause of premature death from the syndrome, followed by complications caused by obesity, including type II diabetes, hypertension and hypercholesterolaemia. Visual prognosis is poor, and the mean age of legal blindness is 15.5 years. Birth weight is typically normal but significant weight gain beigns within the first year. There is considerable interfamilial and intrafamilial variability in the clinical presentation. Genes associated with BBS code for proteins involved in the development and function of primary cilia and absence or dysfunction of BBS proteins results in ciliary anomalies. Pathogenic variants in atleast 16 BBS genes (BBS1 through BBS16) account for approximately 80% of clinically diagnosed BBS patients. In individuals of European and Caucasian ancestry, the majority of mutations are identified in BBS1 and BBS10 which account for 23% and 20% of identified mutations, respectively. In Tunisian populations, pathogenic mutations are more likely to be described in BBS1, BBS2 and BBS8, while in Saudi Arabian populations, pathogenic mutations are more likely to be described in BBS1, BBS3 and BBS4. The panel includes sequence and deletion/duplication analysis of all the listed genes.
