Exploring the molecular basis of Bardet-Biedl syndrome

Few autosomal recessive disorders display the degree of pleiotropism and ge netic heterogeneity found in Bardet-Biedl syndrome (BBS), a genetic disorde r characterized primarily by retinal dystrophy, obesity, polydactyly, cogni tive impairment and gonadal and renal dysgenesis. This relatively rare cond ition has been reported frequently, but we have only recently begun to appr eciate the genetic complexities that give rise to this constellation of cli nical findings. During the last 12 months, the first three of at least six BBS genes have been identified, providing us for the first time with the ab ility to formulate hypotheses regarding the molecular etiology of the disor der. Here we review the key elements of the phenotype and discuss the signi ficance of the discovery of the first three BBS genes on the effort to iden tify the cellular causes of this syndrome.