FDXR and Global developmental delay: From 2017 to 2023, at least 77 patients from more than 50 families were described carrying 59 different biallelic (homozygous or compound heterozygous) FDXR mutations causing a generalized mitochondriopathy, variably presenting with optic atrophy, retinal dystrophy, neuropathic hearing loss, developmental delay, mild movement disorders, and even Leigh syndrome with infantile-onset encephalopathy and death (99-110); this disorder has been termed FDXR-related mitochondriopathy (FRM) (110).