GLYCOGEN STORAGE SIRODERS

Glycogen storage disorders (GSD) are a group of rare defects of the metabolism (lysis an synthesis) of the glycogen, the storage form of glucose in animal cells. These defects usually result in the abnormal glycogen accumulation within several tissues (mainly liver, muscle, kidney, brain).

Several forms have been described (GSD- from 0 to XV): each of them is associated with impairing defects in an enzyme catalyzing one of the steps of glycogen synthesis or demolition.

The severity of the disease depends upon several factors including the residual activity of the enzyme involved. The onset is heterogeneous: perinatal-, infantile-, childhood- and adult-onset presentations have been described.

Main symptoms shared by most of the disorders include: hypoglycemia, hepatomegaly, lactic acidosis, hyperlipidemia, cardiomyopathy, muscle weakness. Specific symptoms are peculiar features of some forms (hepatic adenomas, myoglobinuria, kidney disturbance).

Clinical presentation drives the diagnosis, subsequently confirmed by biochemical and genetic tests.

Dino Ferrari Centre is involved in the study of the following forms of GSD:
– type II, affecting the alpha-glucosidase acid enzyme (GAA, encoded by GAA)
– type III: affecting the debranching enzyme (GDE, encoded by AGL)
– type IV: affecting the branching enzyme (GBE, encoded by GBE1)
– type XIII: affecting beta-enolase activity (ENO, encoded by ENO3)

Available therapies include customized nutrition regimens, physical exercise, enzymatic replacement therapy (ERT, for GSD-II); liver transplantation in case of severe hepatic involvement.