Glycogen Storage Disease Type IV (GSD IV)
GSD IV (Glycogen Storage Disease Type IV) is an inherited disorder affecting glucose metabolism. This inherited deficiency is known in humans, horses, and cats, but among cats, it has only been seen in the Norwegian Forest Cats.
Most affected kittens are stillborn or die soon after birth, presumably due to hypoglycemia (not being able to produce enough glucose "energy") during the birth process and the first hours of life. In very rare cases affected kittens may develop "normally" until 4-5 months of age, they might get some intermittent fever (fever that rises and falls) with tremors and ataxia (lack of control of the movements), then the growth stops and the disease leads progressively to neuromuscular degeneration, to severe muscular weakness, contractions, atrophy and inability to use its limbs (especially the hind legs), to eat, clean itself, to cardiac failures or coma and finally to death before the age of 15 months. But the kitten has presumably already been put to sleep before that age in view of the terrible sufferance.
Mutation and Inheritance
The gene responsible for the disease has been identified by Dr. John Fyfe in the USA, who also developed a gene test for the mutation in Norwegian Forest Cats in 1996. In Europe, this test has been available since 2007. The disease prevalence reported is around 15% in the USA, while statistics in Europe after testing around 2300 cats during a year show 12% carriers.
GSD IV is inherited as a simple autosomal recessive trait, which means that both parents must be carriers of the mutated gene in order to produce affected offspring.
PawPeds has in cooperation with two breed clubs and other interested parties worked out a GSD IV health program starting on 22 October 2008. All breed clubs and other interested cat clubs are very welcome to join the program!