(Forbes disease, glycogen storage disease type III)

Prevalence: 1/100.000. Hepatic glycogen storage disease (type III). Autosomal recessive transmission of mutations of the AGL gene (locus 1p21) resulting in deficiency in amylo1-6-glucosidase (debranching enzyme) preventing the complete degradation of glycogen into glucose: the result is a tendency to hypoglycemia and an accumulation of partially degraded glycogen in the liver and muscle cells. Variable clinical expression: in some cases only the liver or the muscles are affected.

Two clinical forms:

-        form A: with liver and muscle involvement

-        form B:  hepatic involvement only.

The accumulation of dextrin in the liver causes hepatomegaly with hepatic fibrosis and sometimes the apparition of cirrhosis or adenomas. Sometimes a late hypertrophic obstructive cardiomyopathy  (after the age of  30 years). Obesity is a frequent consequence of the diet (frequent meals). Muscle function: sometimes hypotonia in childhood; adulthood: progressive muscular atrophy, starting in the proximal areas, (high CPK levels when the muscle involvement becomes symptomatic.

Anesthetic implications:

-        short fasting time or infusion of a glucose-containg electrolytic solution from the onset of the fasting period to avoid hypoglycemia

-        difficult peripheral venous access

-        sometimes macroglossia

-        monitoring of blood glucose levels and muscle function

-        avoid succinylcholine in case of muscle injury (risk of rhabdomyolysis ?)

-        too frequent inflation of the BP cuff may cause local muscle cramps; use of a surgical  tourniquet is best avoided

References : 

-         Mohart D, Russo P, Tobias JD. 
Perioperative management of a child with glycogen storage disease type III undergoing cardiopulmonary bypass and repair of an atrial septal defect. 
Pediatr Anesth 2002; 12: 649-54.

-         Bolton SD, Clark VA, Norman JE. 
Multidisciplinary management of an obstetric patient with glycogen storage disease type 3. 
Int J Obstetr Anaesth 2011; 20: 86-9.

Updated: September 2019