A rare, likely pathogenic variant causing Leber's hereditary optic neuropathy in three-generation females of an African-American family.

PURPOSE: We report a rare, likely pathogenic variant gene causing Leber's hereditary optic neuropathy (LHON) in three-generation female members of an African-American family.

OBSERVATIONS: The granddaughter and mother presented with a subacute, painless visual loss in both eyes at age 10 and 42 years to legal blindness. The maternal grandmother presented with a gradual onset of moderate visual loss at age 60. The mother and grandmother reported a history of bariatric surgery and subsequent vitamin deficiencies. All three patients shared similar Optical Coherent Tomography (OCT) findings of profound thinning of ganglion cell complex (GCC) and relatively preserved peripapillary retinal nerve fiber layer thickness (pRNFL). Nuclear and mitochondrial DNA sequencing identified a 14596A > T likely pathogenic variant, p.(Ile26Met), in the MT-ND6 gene, with 100% homoplasmy in the granddaughter and mother and 65% heteroplasmy in the grandmother. The mother and grandmother were treated with idebenone in addition to vitamin supplements, with a slight improvement in their vision.

CONCLUSIONS AND IMPORTANCE: Our patients' presentation stresses the importance of including LHON in the differential diagnosis in females presenting with unexplained bilateral, painless, severe visual loss. The OCT finding of profound GCC thinning with relatively preserved pRNFL thickness can be a red flag for LHON. A collaboration with genetic specialists to utilize expanded gene sequencing may greatly enhance our ability to identify rare pathogenic variants.