Isolation and characterization of a candidate gene for Norrie disease

Previous analysis has refined the location of the gene for Norrie disease, a severe, X–linked, recessive neurodevelopmental disorder, to a yeast artificial chromosome sub–fragment of 160 kilobases (kb). This fragment was used to screen cDNA libraries from human fetal and adult retina. As a result, we have identified an evolutionary conserved cDNA, which is expressed in fetal and adult brain and encodes a predicted protein of 133 amino acids. The cDNA detects genomic sequences which span a maximum of 50 kb, and which are partly deleted in several typical Norrie disease patients. An Eco RI polymorphism with a calculated heterozygosity value of 43% was observed. The locus identified is a strong candidate for the Norrie disease gene.