Disorder - Glycogen storage disease IV

Organ Systems Involved
Musculoskeletal

Alternative disorders described within LIDA

Myopathy; Myotonia

Alternative Names
Anderson disease; Brancher deficiency; Amylopectinosis; Familial cirrhosis with deposition of abnormal glycogen; Glycogen branching enzyme deficiency

Presenting Signs

Glycogen storage disease IV is an inherited disorder that affects the metabolism of glycogen, a form of glucose. It is caused by a deficiency of glycogen branching enzyme (alpha-1,4 glucan 6-glycosyl transferase), a protein that helps make glycogen. As a result, abnormal glycogen accumulates in the muscle (both skeletal and cardiac muscles) and nervous tissue. This an recessive genetic trait and is confined to Norwegian Forest Cat only to date.

Most of the affected kittens are stillborn or die within the first few days of life due to hypoglycaemia (low blood sugar). The surviving cats are often clinically normal until five to seven months of age when the skeletal and cardiac muscle progressively degenerates, and they die by 12 to 14 months of age. Clinical signs include intermittent fever, generalised muscle tremors, muscle weakness and wasting, listlessness , a ’bunny-hopping‘ gait, muscle fibre contractions and tetraplegia (paralysis of all four legs). Sudden death may occur as cardiac muscle degenerates and terminal heart dysrhythmia develops.

Breeds Affected
Norwegian Forest Cat


Treatment

None. Short-term supportive fluid therapy with dextrose for management of hypoglycaemia but prognosis is very poor.

PubMed References
Glycogen storage disease IV

Contributor
Shing Cheuk Chan Bird