FXN and nervous system disorder: Contrary to the muscular phenotype of ISCU mutant patients, mutations in other components of the core Fe-S assembly complex cause neurological diseases (eg, Friedreich’s ataxia, MIM 229300, due to FXN mutations) or multisystem disorders (eg, combined oxidative phosphorylation deficiency 19, MIM 615595, due to ISD11/LYRM4 mutations).