An Apparently Isolated Optic Neuropathy Associated with Biallelic Variants in <i>SLC25A46</i> Gene Encoding the Mitochondrial Ugo1-Like Protein

Biallelic pathogenic variants in the <i>SLC25A46</i> gene are responsible for various neurological syndromes, including Charcot-Marie-Tooth disease type 6B, pontocerebellar hypoplasia type 1E, Leigh syndrome, progressive myoclonic ataxia and Parkinson's disease, most of them being associated with optic atrophy. We here report the case of a 26-year-old female patient with a slowly progressive and apparently isolated form of optic neuropathy due to the NM_138773.4:c.[327-2A > T];[410A > G] compound heterozygous variants in this gene. The presence of a subclinical peripheral neuropathy revealed by electroneuromyography confirmed the responsibility of these <i>SLC25A46</i> variants. The absence of functional and structural mitochondrial abnormalities in the patient's fibroblasts was consistent with the mild neurological phenotype. This case report suggests that <i>SLC25A46</i> gene merit consideration during genetic testing for both syndromic and isolated optic neuropathies.