Case report of visual quality in a patient with nephronophthisis 12- associated retinopathy secondary to TTC21B mutation

Nephronophthisis 12 is a rare condition and only two cases have been reported to associate with retinopathy. Herein we present the third case in scientific literature, and the first with vision-quality exams.

The case was a 28-year-old male with the mutations c.626C > T (p.Pro209Leu) and c.1317T > G (p.Tyr439*). Bilateral atrophy of outer retinal layers and retinal pigmented epithelium were observed, resembling a bull’s eye maculopathy. Visual acuity, as well as contrast sensitivity dropped with mesopic conditions. He presented more difficulties in differentiating colors within blue-yellow range, and some degree of halos were detected. Multifocal electroretinogram detected little retinal function, and visual field detected a full scotoma. He referred poorer quality of life due to emotional wellbeing, more than to difficulties in reading or accessing information.

Although rare, nephronophthisis 12 may be caused by genetic mutations that associate severe retinopathy.