Localization of a gene causing cystinuria to chromosome 2p

Cystinuria is an autosomal recessive disorder of amino acid transport. It is a common hereditary cause of kidney stones worldwide, and is associated with significant morbidity. In 17 affected families, we found linkage between cystinuria and three chromosome 2p markers. Maximal two-point lod scores between cystinuria and D2S119, D2S391 and D2S288 were 8.23 (theta = 0.07), 3.73 (theta = 0.15) and 3.03 (theta = 0.12), respectively. Analysis of recombinants and multipoint linkage data indicated that the most likely order is cen-D2S391-D2S119-cystinuria-D2S177-tel. We also observed high rates of homozygosity for markers in this chromosomal region among 11 affected offspring of consanguineous marriages. Based on its map position and function, the recently cloned SLC3A1 amino acid transporter gene is a primary candidate gene for this disease.