Optic Neuropathy AFG3L2 Related in a Patient Affected by Congenital Stationary Night Blindness

Objective: We describe a patient affected by congenital stationary night blindness (CSNB) secondary to CACNA1F and optic neuropathy associated with an AFG3L2 variant. Methods: We performed comprehensive neuro-ophthalmologic examinations, retinal imaging, complete ocular electrophysiology, and brain and optic nerve MRI. Genomic DNA was extracted from the peripheral blood. The patient's DNA was then investigated by next-generation sequencing (NGS) with a panel including 32 genes associated with retinal dystrophy and therefore with a panel including seven genes associated with genetic forms of optic atrophy. Results: The genetic analysis identified a pathogenetic CACNA1F variant causing CSNB and a heterozygous variant in AFG3L2 that alters OPA1 processing and is known to be associated with OPA1-like optic neuropathy. Conclusion: Optic disc atrophy has been previously described as an atypical feature in the phenotype of CSNB CACNA1F-related. In this patient, we found a variant of the AFG3L2 gene that presumably explains the presence of optic atrophy in a subject affected by CSNB. Clinical Relevance: The clinical evidence of optic atrophy, which is atypical in CSNB, should raise the suspicion of concomitant hereditary optic neuropathy and emphasize the importance of broad genetic diagnostic testing to better define the genotype-phenotype correlation.