Three novel mutations causing a truncated protein within the RP2 gene in Italian families with X-linked retinitis pigmentosa.
X-linked retinitis pigmentosa (XLRP) results from mutations in a number of loci, including RP2 at Xp11.3, and RP3 at Xp21.1. RP2 and RP3 genes have been identified by positional cloning. RP2 mutations are found in about 10% of XLRP patients. We performed a mutational screening of RP2 gene inpatients belonging to seven unrelated families in linkage with the RP2 locus. SSCP analysis detected three conformation variants, within exon 2 and 3. Direct sequencing of exon 2, disclosed a G-->A transition at nucleotide 449 (W150X), and a G-->T transversion in position 547 (E183X). Sequence analysis of exon 3 variant revealed an insertion (853/854insG), leading to a frameshift. In this patient, we detected an additional sequence alteration (A-->G at nucleotide 848, E283G). Each mutation was co-segregating with the disease in the affected family members available for the study. These mutations are expected to introduce a stop codon within the RP2 coding sequence probably resulting in a truncated or unstable protein.
De Luca
A
A
Dipartimento di Biopatologia e Diagnostica per Immagini, Università di Roma Tor Vergata, Rome, Italy.
Torrente
I
I
Mangino
M
M
Danesi
R
R
Dallapiccola
B
B
Novelli
G
G
D018388:Codon, Terminator / Q000235:genetics; D005091:Exons; D005136:Eye Proteins; D005260:Female; D016368:Frameshift Mutation; D019204:GTP-Binding Proteins; D008040:Genetic Linkage; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007558:Italy; D008297:Male; D008565:Membrane Proteins; D009154:Mutation; D017354:Point Mutation; D011506:Proteins / Q000235:genetics*; D012174:Retinitis Pigmentosa / Q000235:genetics*; D014960:X Chromosome / Q000235:genetics*
D018388:Codon, Terminator; D005136:Eye Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D011506:Proteins; C072178:RP2 protein, human; D019204:GTP-Binding Proteins