MFN2 and neurodegenerative disease: In this context, proteins that directly modulate mitochondrial fusion have been found mutated in neurodegenerative diseases like Charcot-Marie-Tooth 2A (Mitofusin-2 (Mfn2); [15]) or autosomal-dominant optic nerve atrophy (optic atrophy protein 1 (OPA1); [16,17]).