[Ocular manifestations associated with nephronophthisis and genetic study in three Tunisian families]

Nephronophthisis is a familial interstitial nephropathy with an autosome recessive mode of transmission. In some cases, it is associated with ocular manifestations such as retinitis pigmentosa in Senior-Løken syndrome. We report ocular abnormalities and genetic results in three affected Tunisian families.

Twenty-two members of these three families underwent a complete ophthalmologic examination (visual acuity, slit lamp biomicroscopy, ophthalmoscopy, and retinal electrophysiology). For genetic study, all individuals were genotyped and underwent a genomic sequence.

Twenty-two subjects, nine of whom presented nephronophthisis, were included in this study. Retinitis pigmentosa was found in three cases. Our genetic study demonstrated that patients belonging to family 1 had homozygous deletions in NPHP1, all affected individuals from family 3 were linked to NPHP4 and presented a deletion in exons 2 and 3. Results are pending for patients in family 2.

Senior-Løken syndrome is a rare hereditary disease that combines familial juvenile nephronophthisis and retinitis pigmentosa. This association was described in the literature in 39%-43% of cases. In our study, it was approximately 33% of cases. The genetic study can sometimes obviate the need for renal puncture, especially when the homozygous deletion of NPHP1 gene is confirmed.