SLC37A3-associated retinitis pigmentosa: a case report of clinical features and three-year follow up.

Purpose: To describe a case of SLC37A3-associated retinitis pigmentosa (RP) and associated imaging and electroretinography findings.

Methods: The patient was evaluated at Columbia University Irving Medical Center using a comprehensive multimodal imaging protocol that included color fundus photography, fundus autofluorescence (FAF), and spectral-domain optical coherence tomography. Functional assessments were conducted using full-field electroretinography (ERG), following the ISCEV standard protocols to ensure consistent and reproducible measurements of photoreceptor activity.

Results: A 58-year-old male presented with night blindness beginning in early adulthood. Family history was positive for consanguinity. Dilated fundus exam revealed mild optic disc pallor, small perivenous hyperpigmentation greater nasally, and spared foveal islands in both eyes. FAF demonstrated a hyperautofluorescent ring around the macula in a bull's eye pattern and hypoautofluorescent lesions along the arcades and nasally. ERG results supported a diagnosis of rod-cone dystrophy. Initial genetic panel testing and whole exome sequencing were inconclusive, but whole genome sequencing identified homozygous mutations in the SLC37A3 gene.

Discussion: This report expands upon the sparse clinical data on SLC37A3-associated RP and supports the observation that a nasal predominance of retinal pigment may be a distinguishing clinical feature. Additionally, this case underscores the diagnostic value of whole-genome sequencing, especially when initial targeted genetic panels or whole-exome sequencing yield negative results. The metabolic role of SLC37A3, potentially linked to intracellular glucose transport, suggests a novel pathway in RP pathogenesis that warrants further study. Advances in gene-specific natural history characterization will be critical as gene-targeted therapies evolve, particularly for rare genetic forms of RP such as this case.