Leber hereditary optic neuropathy (LHON) with dystonia
is a very rare variant of LHON where an individual has LHON associated with dystonia, which involves involuntary muscle contractions, tremors, and other unctrolled movements. It is caused by mutations in one of three mitochondrial genes: MT-ND1, MT-ND3, MT-ND4, and MT-ND6. Other features that have been associated with this condition include difficulty walking, muscle wasting, scoliosis, dysphagia, dysarthria, intellectual disability, dementia, and spasticity. The dystonia usually begins in childhood; vision loss may begin in early adulthood. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.