COG5-congenital disorder of glycosylation (Monarch Disease Ontology term MONDO_0013325) can be described as follows. COG5-CDG is an extremely rare form of CDG syndrome characterized clinically in the single reported case to date by moderate mental retardation with slow and inarticulate speech, truncal ataxia, and mild hypotonia. Also known as: CDG syndrome type III, CDG-III, CDG2I, COG5-CDG, carbohydrate deficient glycoprotein syndrome type III, congenital disorder of glycosylation type 2i, congenital disorder of glycosylation type III.