Bardet–Biedl syndrome is linked to DNA markers on chromosome 11 q and is genetically heterogeneous

Bardet–Biedl syndrome (BBS) is an uncommon autosomal recessive condition characterized by mental retardation, post–axial polydactylia, obesity and pigmentary retinopathy. We performed linkage analysis in 31 multiplex BBS families and report significant linkage with two markers on chromosome 11 q, PYGM and AFM164zf12 (D11S913). Homogeneity testing demonstrates genetic heterogeneity within our set of families. Our data imply that a major gene, BBS1, is located on chromosome 11q, although mutations at other loci may also be associated with this phenotype.