Abnormal isoelectric focusing of serum transferrin Type I transferrin isoform profile HP:0003642 Abnormal transferrin isoform profile consistent with a type I congenital disorder of glycosylation. In the traditional nomenclature for congenital disorders of glycosylation, absence of entire glycans was designated type I, and loss of one or more monosaccharides as type II. Type 1 transferrin isoform profile Abnormal isoelectric focusing of serum transferrin, type I pattern Isoelectric focusing of serum transferrin consistent with CDG type I UMLS:C1837899 There are several methods in use with which this feature can be diagnosed. Using HPLC analysis an increased asialo- and disialotransferrin and reduced tetrasialotransferrin are observed. Using immunoaffinity column analysis, the mono-oligosaccharide/di-oligosaccharide transferrin ratio, and/or the a-oligosaccharide/di-oligosaccharide transferrin ratio are abnormal.