CRPPA and congenital muscular dystrophy: Our rationale for this was that mutations in ISPD are causal for CMD (Roscioli et al., 2012; Willer et al., 2012), ISPD is a putative nucleotidyltransferase found in the cytosol (Vuillaumier-Barrot et al., 2012), and homologs in bacterial systems are involved in the generation of identical, CDP-ribitol (Baur et al., 2009), or similar structures, 4-CDP-2-C-methyl-D-erythritol (Richard et al., 2001).