Background: Fourteen loci have been associated with autosomal dominant cataract, but only one with the recessive form of the disease.
Objectives: To find the chromosomal location of a gene causing autosomal recessive cataract in three inbred Arab families.
Methods: A single nucleotide polymorphism-based genome-wide search, with the Effvmetrix GeneChip HuSNP genotyping array, was performed on a pooled DNA sample from six affected family members in a search for regions showing homozygosity. Using conventional microsatellite markers, regions of homozygosity were further analyzed in all the families.
Results: A region on chromosome 3p spanning 43 megabases showed homozygosity with 13 consecutive SNPs. Three microsatellite markers from this region yielded lod scores > 3.00. A maximal two-point lod of 4.83 was obtained with the marker D3S1298 at theta = 0.004. Haplotype analysis placed the disease gene in a 20 Mb interval between D3S1768 and D3S2409.
Conclusions: A gene causing autosomal recessive cataract maps to the short arm of chromosome 3.