[Molecular exploration of the R91W (RPE65 gene) in Tunisian patients with early onset retinal dystrophy and early onset retinitis pigmentosa].

BACKGROUND

Inherited retinal dystrophies are the major causes of blindness and visual impairment. Visual loss is due to neurosensory retinal and pigment epithelium cells degeneration. The most severe were Leber Congenital amaurosis (LCA), juvenile retinitis pigmentosa (RP) and early onset RP. The LCA and juvenile RP are called «Early Onset Retinal Dystrophy» (EORD).

OBJECTIVE

Molecular exploration of the R91W (RPE65 gene) in Tunisian patients with Early Onset Retinal Dystrophy and early onset RP.

METHODS

All patients underwent a complete ophthalmological and a general examinations. The R91W exploration was performed by direct sequencing of exon 4 of the RPE65 gene and enzyme digestion.

RESULTS

Among 47 patients, 13 were from Nabeul. Twenty three had an EROD with a visual loss under the age of 2 years. Twenty four were with early onset RP and had these symptoms between the ages of 4 and 10 years. The best corrected visual acuity ranged from 2/10 to 1/60. Among the explored 94 chromosomes, the R91W (325C>T) allele was identified in heterozygous state in a sibling from Nabeul. The allele frequency was 2.12% (2/94).

CONCLUSION

All our patients had severe forms of RP with a decrease in visual acuity and a wide advanced retinal degeneration. The R91W mutation (325C>T) was not the major cause of EORD and early onset RP among Tunisian patients.