In humans, mutations in gene COG1, COG4, COG5, COG6, COG7, and COG8 have been reported to be associated with CDG (Wu et al., 2004; Foulquier et al., 2006; Foulquier et al., 2007; Reynders et al., 2009; Rymen et al., 2015; Kim et al., 2017). Here, COG5 is linked to congenital disorder of glycosylation.