THE CARBOHYDRATE-DEFICIENT GLYCOPROTEIN SYNDROMES - AN OVERVIEW

The carbohydrate-deficient glycoprotein (CDG) syndromes are a newly re cognized family of diseases with autosomal recessive inheritance. The basic defects are probably in the glycosylation pathway (endoplasmic r eticulum, Golgi apparatus or post-Golgi). In the present state of our knowledge the central nervous system is always severely affected but n early all other organs are involved to a variable degree. Like the per oxisomal disorders they also comprise dysmorphic features. the most ty pical being an abnormal distribution of subcutaneous adipose tissue. A reliable diagnostic test is isoelectric focusing of serum transferrin showing a cathodal shift as a consequence of the partial sialic acid deficiency. Prenatal diagnosis and heterozygote detection are not yet available. These diseases should be differentiated from secondary CDG syndromes such as classical galactosaemia.