Genetic causes of acute visual loss

Abstract

AbstractGenetic causes of acute visual loss are relatively rare, but these still need to be considered in the differential diagnosis, especially in the relevant clinical context. In this presentation, classical genetic disorders affecting the optic nerve will be discussed with a particular focus on Leber hereditary optic neuropathy (LHON). LHON is a primary mitochondrial DNA (mtDNA) disorder and three point mutations within the mitochondrial genome account for the vast majority of cases, namely: m.3460G>A, m.11778G>A and m.14484T>C. It typically affects young adult males who present with bilateral severe visual loss in the second or third decade of life. In addition to the canonical LHON mutations, other pathogenic mtDNA mutations have been reported that can result in both syndromic and non‐syndromic optic neuropathies. Acute visual loss in genetic disorders can also be secondary to pathology involving the retrochiasmal visual pathways, for example, in MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke‐like episodes). The cardinal clinical manifestations in this group of patients are homonymous hemianopic visual field defects or cortical blindness.