Defects in several proteins involved in the biosynthesis and trafficking of [4Fe-4S] clusters are associated with multiple mitochondrial dysfunctions syndromes (MMDS), with NFU1 causing MMDS1, BOLA3 causing MMDS2, IBA57 causing MMDS3, ISCA2 causing MMDS4, and ISCA1 causing MMDS5 (Navarro-Sastre et al., 2011; Cameron et al., 2011; Torraco et al., 2017; Lossos et al., 2015; Shukla et al., 2017; Al-Hassnan et al., 2015; Torraco et al., 2018). The gene discussed is NFU1; the disease is multiple mitochondrial dysfunctions syndrome 1.