Clinical and imaging characteristics of posterior column ataxia with retinitis pigmentosa with a specific FLVCR1 mutation.

Background: Posterior column ataxia retinitis pigmentosa (PCARP) with feline leukemia virus subgroup C cellular receptor 1 (FLVCR1) gene mutation is a rare disorder with significant ophthalmic features.
Materials and Methods: We conducted a retrospective case series study of patients diagnosed with PCARP and genetic testing positive for FLVCR1 mutation between 1 January 2015 and 1 October 2017 at the Children's Hospital of Pittsburgh. Clinical charts, visual fields, fundus autofluorescence, and spectral-domain optical coherence tomography (SD-OCT) were reviewed.
Results: Seven patients from three families were identified to have PCARP and FLVCR1 mutation. The median age at presentation was 13 years (range, 7-28 years). Common clinical exam findings were astigmatism, cataracts, and vitreous syneresis. Funduscopy on all patients revealed bull's eye maculopathy, retinal vessels attenuation, and bone spicule changes in the peripheral retina. Fundus autofluorescence showed bilateral hyperautofluorescent rings. SD-OCT demonstrated morphological changes, which differed based on age. The youngest sibling family exhibited peripheral loss, but subfoveal preservation of the outer retinal layers. These layers were lost in the oldest sibling family. Visual fields loss paralleled SD-OCT findings.
Conclusion: There is limited published ophthalmic data on FLVCR1-related PCARP. We describe clinical and retinal imaging features in the one of the largest cohorts of affected patients in the literature. Given the availability of genetic testing for this phenotype, testing for FLVCR1 mutations should be considered in pediatric and adult patients with sensory ataxia and retinitis pigmentosa.