MFN2 and Optic neuropathy: Using whole-exome sequencing, we screened for variants in unrelated patients presenting inherited optic neuropathies (ION) with a negative molecular diagnosis after analyzing OPA1, OPA3, WFS1, SPG7, AFG3L2, DNM1L, MFN2 exonic sequences, and pathogenic variants in the mitochondrial DNA responsible for LHON.