Type I pattern

An aberrant pattern of transferrin glycosylation typical of defects in N-linked protein glycosylation that occur in the ER prior to the attachment of the oligosaccharide precursor to the protein; characterized by low overall levels of glycosylation with elevated levels of asialo- (no sialic acids) or monosialotransferrin (one sialic acid) isoforms, instead of the normal tetrasialotransferrin.