[Congenital disorders of glycosylation and project "Euroglycanet"].

Congenital disorders of glycosylation are rapidly growing group of inborn errors of metabolism caused by defects in the biosynthesis of glycoproteins. Primary disorders are due to enzyme deficiencies, resulting in defects of assembly, transfer or processing of carbohydrate side chains, leading to incomplete glycosylation of plasma proteins. They comprise disorders of N-glycosylation, O-glycosylation and combined disorders. Congenital disorders of N-glycosylation are multisystem diseases with wide variation in clinical presentation including mental retardation, severe developmental delay, seizures, malformations, structural abnormalities of central nervous system, liver fibrosis, hormonal and coagulation disorders, etc. In contrary, O-glycosylation disorders are often organ restricted and have characteristics of congenital malformations. Isoelectric focusing of serum transferrin is the accepted screening method for many of N-glycosylation disorders. In the last two years the method is available in Croatia. The aim of this article is to point out congenital disorders of glycosylation as possible causes of multisystem disorders of unknown origin, especially when central nervous system symptoms or liver fibrosis are present. "Euroglycanet" is a project set up by European medical doctors, in particular geneticists, and glycobiologists with the purpose to exchange experiences and knowledge and to improve research, diagnosis and treatment of congenital disorders of glycosylation.