Ocular Biomarkers of Riboflavin Transporter Deficiency. Issue 1 (2nd March 2023)

• Record Type: Journal Article
• Authors: Bulas, Sabrina; Bedoukian, Emma C.; O'Neil, Erin C.; Krantz, Ian D.; Yum, Sabrina W.; Liu, Grant T.; Aleman, Tomas S.
• Editors: Fraser, Clare; Mollan, Susan
• Is Part Of: Journal of neuro-ophthalmology. Volume 43:Issue 1(2023)
• Page Start: 110
• Page End: 115
• Publication Date: 2023-03-02
• Subjects: Neuroophthalmology -- Periodicals; 617.7
• DOI: 10.1097/WNO.0000000000001678
• Languages: English
• ISSNs: 1070-8022

Abstract

Abstract : Background: To describe the clinical presentation with a focus on ocular manifestations and response to riboflavin supplementation of 3 patients with riboflavin transporter deficiency (RTD) caused by mutations in SLC52A2 ( SLC52A2- RTD). Methods: This is a retrospective review of records of 3 children (aged 18, n = 2 and age = 8, n = 1) with SLC52A2- RTD. Patients underwent comprehensive ophthalmic evaluations including color vision testing, pattern visual-evoked potentials (pVEPs, 1 patient) and spectral domain optical coherence tomography (SD-OCT) imaging. Patients received riboflavin supplements from the time of the molecular diagnosis of RTD. Results: Two unrelated 18-year-old patients with SLC52A2- RTD had a symptomatic onset with sensorineural hearing loss and auditory neuropathy/dys-synchrony since age 3 and 11, respectively. On examination 7 years after symptomatic onset, they showed subnormal visual acuities (20/30 and 20/60, both eyes, respectively), preserved color vision, and a thin but measurable retinal ganglion cell layer (GCL) and nerve fiber (RNFL). The inner and outer nuclear layers were normal. The asymptomatic SLC52A2- positive brother of one of these patients started riboflavin supplementation right after the molecular diagnosis and had normal vision and SD-OCTs 7 years later. Onset of riboflavin supplementation in one of the 2 symptomatic cases resulted in acute improvement of the pattern visual-evoked potential and vision. Conclusions: Retinal ganglion cells and their axons are uniquely susceptible to RTD compared with other highly energy-dependent retinal neurons, such as photoreceptors, raising the possibility for alternative mechanisms of disease or protection. Riboflavin supplementation results in acute functional improvement of vision and long-term preservation of GCL and RNFL if initiated early.