Glycogen storage disease type IV is an inherited abnormality of glucose metabolism that is seen in Norwegian Forest cats.
It is inherited as a simple autosomal recessive trait and can manifest in two ways:
- By far the most common form is stillbirth or death within a few hours of birth. This probably results from the kittens having insufficient glucose to produce energy during the birth process and the first hours of life.
- On rare occasions, an affected kitten will survive the neonatal period and appear normal until 5 months of age. Though less common, this is the more devastating form of the disease because by this age new owners are attached to their kitten, and have to watch it go through months of neuromuscular degeneration. By 8 months of age, affected kittens have severe muscular weakness, atrophy and contraction, and an inability to use their limbs. Affected cats may die suddenly from heart failure.
A DNA test is available for the diagnosis of affected kittens and the detection of carrier cats.