PUS1 and sideroblastic anemia: Second, understanding the biology of Pus1 could shed light on the biology of human PUS1, mutation of which has been associated with the rare autosomal recessive disease mitochondrial myopathy and sideroblastic anemia (MLASA) and the related condition congenital sideroblastic anemia (CSA) (Bykhovskaya et al. 2004; Fernandez-Vizarra et al. 2007; Bergmann et al. 2010; Fujiwara and Harigae 2013).