"Carbohydrate-deficient glycoprotein" syndrome.

Carbohydrate-deficient glycoprotein syndrome (CDGS) is a newly delineated g roup of inherited multisystemic disorders associated with abnormal glycosyl ation of a number of serum glycoproteins. Several types have been described on the basis of clinical presentation and biochemical changes of the glyco sylation of serum transferrin and attributed to different enzymatic defects , their clinical presentations are fully different and a clinical heterogen eity is observed within a same type of CDGS. Patients with CDGS type la usu ally present with neurologic (hypotonia, strabismus and cerebellar hypoplas ia) and cutaneous (inverted nipples, abnormal distribution of adipose tissu e) abnormalities, together with multivisceral involvement (digestive, hepat ic, cardiac, renal). However, neurologic and cutaneous symptoms may be abse nt, so that CDGS must be looked for in case of unexplained organ failure su ch as isolated liver insufficiency; cardiomyopathy: pericarditis, tubulopat hy, nephrotic syndrome, vascular accident or retinitis pigmentosa. Patients with CDGS type Ib present with liver disease, enteropathy and hypoglycemia without neurologic involvement. These patients are successfully treated wi th oral mannose administration, emphasizing the importance of making the di agnosis. Patients with CDGS type Ic present with mild psychomotor retardati on and seizures. Patients with CDGS type II have psychomotor retardation as sociated with severe gastrointestinal disorder dysmorphic features and abno rmal electroretinogram. Other types (III, IV) are less clearly defined and the clinical presentation includes convulsive encephalopathy. Biological ab normalities such as mild hepatic cytolysis, hematologic and hormonal abnorm alities are consistently observed in CDGS type I, as well as renal hyperech ogeneity, leading one to look for this syndrome when they are associated. U ntil now, only four enzymatic deficiencies have been identified (types la, Ib, Ic, II). (C) 2000 Editions scientifiques et medicales Elsevier SAS.