[MIM 300559, 326 750, 306 000, 613 027, 261 750]

(glycogen storage disease type VIII or IX) 

Very rare. Deficiency in phosphorylase b-kinase . The enzyme is composed of 4 subunits (α, β, δ, γ). Phosphorylase a is located in hepatocytes, phosphorylase b in the muscle cells. The deficiency in phosphorylase a is also called glycogen storage disease VI. 

Five different clinical presentations depending on the type of transmission and the  tissue involved.

1) X-linked liver disease of childhood (PHKA2 gene on Xp22)

2) muscle and liver disease of autosomal recessive transmission (PKHB gene on 16q): hypoglycemia, very severe hepatosplenomegaly; reduced exercise tolerance.

3) myopathy: X-linked transmission (PHKA1 gene on Xq12-q13) ; very similar to Mc Ardle disease but less severe

4) severe liver disease with cirrhosis, autosomal recessive transmission (PHKG2 gene on 16p)

5) fatal infantile hypertrophic cardiomyopathy due to the deficiency in the enzyme at the cardiac level

Anesthetic implications: 

monitor blood glucose levels; check liver function, avoid tourniquets and muscle compression.

References : 

-        DiMauro S, Spiegel R. 
Progress and problems in muscle glycogenoses. 
Acta Myologica 2011; 30: 96-102.

-        Rocha CT.        
Metabolic muscle disorders in infants and children.        
J Pediatr Biochemistry 2014 ; 4 : 231-248.

Updated: June 2017