Type 2 vasopressin receptor gene, the gene responsible nephrogenic diabetes insipidus, maps to Xq28 close to the LICAM gene.

Although long contigs have been assembled in Xq28, the interval between the anonymous probe St14 and the color vision locus is still incompletely defined. We report here that the recently cloned gene for type 2 vasopressin receptor (V2R) is physically linked to L1CAM using YACs and cosmids across about 180 kb of the region. Since it is known that L1CAM maps near the color pigment genes, this finding locates V2R in Xq28 in the area where nephrogenic diabetes insipidus (NDI) has been mapped by linkage analysis. The PFGE analysis of the clones positions V2R about 40 kb from the L1CAM gene in a region that appears to contain other unknown genes, since at least four putative CpG islands were identified by restriction analysis with rare cutter enzymes.