Congenital disorders of glycosylation is a group of very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type Ih is caused by a defect on chromosome 11pter-p15.5 and involves the gene for a particular enzyme (dolichyl-P-glucose:Glc-1-Man-9-GlcNAc-2-PP-dolichyl-alpha-3-glucosyltransferase). See also Congenital disorder of glycosylation type 1H