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Clinical aspects of Autosomic Recessive Retinitis Pigmentosa Caused by USH 2A Mutations in Consanguineous Tunisian Families
Author(s) -
Chebil A.,
Largueche l.,
Kort F.,
Hassairi A.,
Habibi I.,
Munier F.,
El Matri l.
Publication year - 2015
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2015.0465
Subject(s) - retinitis pigmentosa , abca4 , electroretinography , ophthalmology , fundus (uterus) , visual acuity , usher syndrome , retinal degeneration , consanguineous marriage , medicine , biology , genetics , retinal , consanguinity , phenotype , gene
Purpose To assess the clinical phenotype in consanguineous Tunisian families with non syndromic autosomic recessive retinitis Pigmentosa (ar RP ) caused by an USH 2A mutation. Methods All accessible members of families were included and underwent full ophthalmic examination with best corrected Snellen visual acuity, kinetic visual field testing, fundus photography, optical coherence tomography and full field electroretinography. Haplotype analyses were used to test linkage in the families to 20 ar RP loci, including ABCA 4, LRAT , USH 2A, RP 29, CERKL , CNGA 1, CNGB 1, CRB 1, EYS , RP 28, MERTK , NR 2E3, PDE 6A, PDE 6B, RGR , RHO , RLBP 1, TULP 1. Results Thirty‐four patients from five families were ascertained for the study. Twelve of the 34 members were clinically affected with arRP without hearing loss. Age range at baseline was 27–68 years (mean age was 42.5 years). For all affected members, night blindness appeared during the second decade. Visual acuity at baseline ranged from 20/40 to 20/32. Kinetic visual field was severely constricted. Fundus examination revealed typical RP changes with bone spicule‐shaped pigment deposits in the mid periphery along with atrophy of the retina, narrowing of the vessels and waxy optic discs. Tomograms showed a thinning and even loss the outer nuclear layer of the fovea. ERG was unrecordable in scotopic conditions and the cone responses were markedly hypovolted. Conclusions For these families, changes were typical of those that have been described in patients with moderate to severe forms of non syndromic recessive RP . Our findings support the need to consider possible involvement of USH 2A not only in patients with Usher syndrome but also in patients with non syndromc ar RP . Despite consanguinity, the presence of non‐homozygous mutants illustrates the complexity of molecular analysis.