ated mutations???G3460A, G11778A, and T14484C???indeed developed optic neuropathy.2,38Table 2.Summary of Clinical and Molecular Data for 17 Chinese Families Carrying the ND4 G11778A MutationThe wide range of phenotypic variability of matrilineal relatives within and among families including the severity, age at onset, and penetrance of visual impairment indicated the involvement of other modifier