BBS8 is one of the eight genes identified to date for Bardet-Biedl syndrome (BBS)-an autosomal recessive condition associated with retinitis pigmentosa, obesity, polydactyly, cognitive impairment and kidney failure. The identification of BBS8 gave the key to the pathogenesis of the condition as a primary ciliary disorder. To date, only three families mutated in the BBS8 gene have been reported. Here, we report on three additional families with BBS8 mutations from a series of 128 BBS families. Two of the three families have homozygous mutations and one has a heterozygous mutation. Mutations in BBS8 probably account for only a minority of BBS families (2%), underlining the difficulty of genotyping heterogeneous conditions.