[Congenital disorders of glycosylation - constantly growing group of metabolic diseases].

Congenital disorders of glycosylation (CDG) are a group of genetic disorders caused by abnormal N- and O-glycosylation pathway of proteins and lipids. The glycosylation process plays an important role in the proper functioning of the body and its disorder leads to serious clinical defects. The clinical picture is extremely heterogeneous, including symptoms involving many organs or systems with predominantly neurological manifestation.A broad clinical phenotype poses a challenge in CDG diagnosis. A large group among CDG are defects associated with protein N-hypoglycosylation. A simple test its diagnosis is isoelectrofocusing (IEF) of serum transferrin which is still the "gold standard" in the diagnostics. Normal isoform transferrin profile does not rule out all glycosylation defects. Molecular diagnostics play an important role and the dissemination of next generation sequencing (NGS) has allowed new disorders to be identified.