IDENTIFICATION OF 2 ALLELIC MUTATIONS IN THE BETA-SUBUNIT OF PHOSPHODIESTERASE GENE IN A SPANISH FAMILY WITH RECESSIVE AUTOSOMIC RETINITIS-PIGMENTOSA

BACKGROUND: Retinitis pigmentosa (RP) is a group of inherited eye diso rders that affect photoreceptor and pigment epithelial function. Mutat ions in different genes involved in the phototransduction process have been described in patients with autosomal recessive RP. PATIENTS AND METHODS: We examined the gene coding the beta subunit of the phosphodi esterase (PDEB) in a ARRP family with two affected sisters. SSCP (sing le stand conformational polymorphism) analysis of the coding region of the gene showed abnormal bands in two different exons. PCR products s howing SSCP aberrant patterns were subsequently sequenced. RESULTS: Th e two affected sisters had inherited from their father a PDEB gene wit h a known mutation (Gln298X) and a rare variant and from their mother a PDEB gene with a new mutation: Asp600Asn. CONCLUSIONS: The nature of the mutations in the PDEB gene and their pattern of inheritance indic ate that the lack of activity of the phosphodiesterase (PDE), a key en zyme in the visual phototransduction process, account for the RP pheno type in these patients.