COA8 and hyperinsulinemic hypoglycemia, familial, 4: The absence of COA8 (or its orthologues) was consistently associated with COX deficiency in human tissues (OMIM #616003), cells and in animal models (Yasuda et al., 2006; Sun et al., 2008; Signes et al., 2019; Brischigliaro and Zeviani, 2021).