Novel variants of RPGR in X-linked retinitis pigmentosa families and genotype-phenotype correlation
To identify novel mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene and retinitis pigmentosa 2 (RP2) gene underlying X-linked retinitis pigmentosa (XLRP) and assess genotype-phenotype correlations.
The patient cohort, consisting of 13 individuals from 3 unrelated XLRP families, underwent comprehensive ophthalmologic examination. The open reading frames of RPGR and RP2 were analyzed with Sanger sequencing in each patient. The identified genetic variants were defined as mutations or polymorphisms on the basis of their pathological effect.
We found 3 genetic variants: a novel mutation c.1591G>T in exon 14 and a novel polymorphism c.1105C>T in exon 10, resulting in p.Glu531* and p.Arg369Cys of RPGR gene, respectively, and one already known mutation c.413A>G in exon 2, resulting in a p.Glu138Gly of RP2 gene. Considering our XLRP probands, RPGR-related phenotypic damages were similar and less severe than those of the patient with the RP2 mutation. On the other hand, the female carriers of XLRP variants showed different RPGR-related consequences, ranging from rods hypofunctionality in c.1591G>T nonsense heterozygosity to no retinal changes in c.1105C>T polymorphic heterozygosity.
These findings broaden the spectrum of RPGR mutations and phenotypic variability of the disease, which will be useful for genetic consultation and diagnosis in the future.
Eur J Ophthalmol 2017; 27(2): 240 - 248
Article Type: ORIGINAL RESEARCH ARTICLE
Francesco Parmeggiani, Vanessa Barbaro, Angelo Migliorati, Paolo Raffa, Patrizia Nespeca, Katia De Nadai, Claudia Del Vecchio, Giorgio Palù, Cristina Parolin, Enzo Di Iorio
• Accepted on 31/08/2016
• Available online on 21/10/2016
• Published in print on 10/03/2017
Financial support: This research was supported by the Healthcare Research Funding Grant of the Veneto Region (Project Code No. 330/2010) and by the Research Funding Grant of the RP Triveneto Onlus Nonprofit Association (Project Code No. DIIO_EPPR_P13_03). None of the funding organizations had a role in the design or conduct of the research.
Conflict of interest: None of the authors has conflict of interest with this submission.
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