COQ4 and Leigh syndrome: Moreover, some of the genes that were downregulated in the absence of IRF-5, like Ndufaf3 and Coq4, are associated with mitochondrial disorders in humans (Brea-Calvo et al, 2015; Saada et al, 2009; van der Ven et al, 2023) and with the Leigh syndrome (Baertling et al, 2017).