Investigation of Congenital Disorders of Glycosylation by Transferrin Isoelectric Focusing (CAT#: STEM-ET-0359-ZJF)

Introduction

Congenital disorders of glycosylation (CDG) are genetic diseases that affect the synthesis and processing of glycans from glycoproteins and glycolipids, of autosomal recessive inheritance for the most part, characterized by total or partial deficiency of proteins involved in protein or lipid glycosylation. There are two main types of protein glycosylation: N-glycosylation and O-glycosylation. N-glycosylation (binding of N-glycans to the amino group of asparagine) comprises an assembly step and a processing step that covers three distinct compartments: cytoplasm, endoplasmic reticulum, and Golgi complex. O-glycosylation (binding of O-glycans to threonine or serine hydroxyl groups) has no processing step and consists only of the assembly step. Thus, there are CDGs that involve N-glycosylation only, O-glycosylation only, or both. It is estimated that 94% of individuals with CDG have N-glycosylation defects, with the most frequent being PMM2-CDG (formerly CDG Ia) and ALG6-CDG (formerly CDG Ic). To characterize cases of suspected congenital disorders of glycosylation (CDG), this service provides a method using the transferrin isoelectric focusing TfIEF test.