A NOVEL MUTATION IN EXON-17 OF THE BETA-SUBUNIT OF ROD PHOSPHODIESTERASE IN 2 RP SISTERS OF A CONSANGUINEOUS FAMILY

We report the molecular analysis of the beta subunit of the rod phosph odiesterase (PDEB) gene in a consanguineous autosomal recessive retini tis pigmentosa family that shows homozygosity for polymorphisms in the genomic region comprising this gene, and positive linkage between a P DEB marker and the diesease. The two affected sisters are homozygous f or a T to G transversion in codon 699 of the PDEB gene, leading to the substitution of a leucine by an arginine residue. This change, enclos ed in the catalytic domain of the PDEB, could result in a modification of the protein structure preventing the physiological hydrolysis of c GMP.