Evaluation of serum transferrin microheterogeneity for the diagnosis of congenital N-glycosylation defects

Introduction: transferrin is a glycoprotein produced in the liver, whose function is to transport iron to the tissues. It has been used mainly for the differential diagnosis of anemias as a biomarker. There are different isoforms due to the difference in their glycosylation patterns. This microheterogeneity has allowed its use as a biomarker for Congenital Disorders of Glycosylation; genetic diseases as a result of mutations in genes that encode the enzymes of the post-translational mechanism of protein glycosylation.Objective: to evaluate the microheterogeneity of serum transferrin for the diagnosis of Congenital Disorders of Glycosylation in CubaMethods: a descriptive and cross-sectional study was developed at the National Center for Medical Genetics in the period from 2016 to 2022. The analytical method used was the transferrin isoelectric focusing with immunofixation described by Van Eijik et al in 1983. Serum samples from 26 patients with multisystem clinical symptoms and suspicion of having a genetic disease without a definitive di-agnosis were processedResults: the IEF with immunofixation used allowed us to determine the glycosylation pattern of serum Tf. An altered Tf glycosylation pattern was found in four samples, two of type I and two of type II.Conclusions: the IEF method to evaluate Tf glycoforms allowed the positive diagnosis in four patients, thus demonstrating the presence of Congenital Disorders of Protein N-glycosylation in Cuba