Any of several heritable diseases characterized by the abnormal storage and accumulation of glycogen in the tissues, esp. in the liver. These diseases are grouped into various types according to the enzyme deficiency responsible. SYN: glycogenosis.

phosphorylase b kinase deficiency g.s.d.A glycogen storage disease caused by an X-linked deficiency of the kinase that activates phosphorylase. It was previously called type VIa, VIII, or IX.

g.s.d. type Ia A glycogen storage disease with onset usually in the first year of life. This autosomal recessive genetic disorder is due to a glucose-6-phosphatase deficiency. SYN: Gierke disease.

g.s.d. type Ib A glycogen storage disease similar to type Ia but occurring at only one tenth its frequency. The disorder is due to a deficiency of glucose-6-phosphatase microsomal translocase.

g.s.d. type II A glycogen storage disease caused by a deficiency of lysosomal α-glucosidase. SYN: Pompe disease.

g.s.d. type III A glycogen storage disease caused by a deficiency of two debranching enzymes in liver and muscle tissues. SYN: Forbes disease.

g.s.d. type IV Adult polyglucosan body disease.

g.s.d. type V McArdle disease

g.s.d. type VI A glycogen storage disease caused by a deficiency of liver phosphorylase and characterized by growth retardation, hepatomegaly, hypoglycemia, and acidosis.

g.s.d. type VII Phosphofructokinase deficiency.