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

Introduction: 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.

Clinical case: 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.

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