Screening for mutations in RPGR and RP2 genes in Jordanian families with X-linked retinitis pigmentosa.
Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous disease causing progressive degeneration of retinal photoreceptor cells. X-linked RP (XLRP), in which photoreceptor degeneration begins in early childhood and complete blindness often occurs by the fourth decade of life, constitutes the most severe form of this disease. Two genes commonly associated with XLRP have previously been cloned: retinitis pigmentosa GTPase regulator (RPGR) and retinitis pigmentosa 2 (RP2). We sought to identify mutations in these genes in Jordanian families suffering from this disease. Five unrelated Jordanian families with confirmed XLRP were screened for such mutations using direct sequencing. Three mutations were identified in the ORF15 exon of RPGR. The silent g.ORF15+470G>A substitution and the g.ORF15+1822insA insertion in the 3ꞌ-untranslated region were found in both normal and affected male family members at comparable frequencies, and thus were considered normal variants. The third mutation, g.ORF15+588G>A, in which alanine is substituted by threonine, was found in all affected men and one unaffected man in the two families harboring this variant. Thus, this mutation may be pathogenic, but with incomplete penetrance. No RP2 mutations were found among the examined families. Mutation screening of RP patients is essential to understand the mechanism behind this disease and develop treatments. A complete family history is required to identify its inheritance pattern and provide genetic counseling for patients and their families.
Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan.
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Haddad
Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan.
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Khabour
Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan.
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Abuzaideh
Faculty of Medicine, Jordan University of Science and Technology, Irbid, Jordan.
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Shihadeh
D000293:Adolescent; D000328:Adult; D002648:Child; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics; D005136:Eye Proteins / Q000235:genetics*; D005260:Female; D019204:GTP-Binding Proteins; D005817:Genetic Counseling; D040181:Genetic Diseases, X-Linked; D008040:Genetic Linkage; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D009154:Mutation; D016366:Open Reading Frames; D010375:Pedigree; D010641:Phenotype; D012174:Retinitis Pigmentosa / Q000235:genetics* / Q000473:pathology
D005136:Eye Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C072178:RP2 protein, human; C099929:RPGR protein, human; D019204:GTP-Binding Proteins