Identification of the gene that, when mutated, causes the human obesity syndrome BBS4

Bardet–Biedl syndrome (BBS, MIM 209900) is a heterogeneous autosomal recessive disorder characterized by obesity, pigmentary retinopathy, polydactyly, renal malformations, mental retardation, and hypogenitalism1,2,3,4. The disorder is also associated with diabetes mellitus, hypertension, and congenital heart disease4,5,6. Six distinct BBS loci map to 11q13 (BBS1), 16q21 (BBS2), 3p13–p12 (BBS3), 15q22.3–q23 (BBS4), 2q31 (BBS5), and 20p12 (BBS6)7,8,9,10,11,12,13. Although BBS is rare in the general population (