Breeds Affected: Norwegian Forest Cat
Samples Accepted: Blood, Buccal Swabs
Disease Information: GSD IV is a glycogen storage disorder. Affected kittens are usually stillborn, or die shortly after birth. If affected kittens survive the perinatal period, they are often clinically normal until approximately 5 months of age, when they exhibit hyperthermia (high temperature) and progressive muscle tremors, muscle atrophy, and eventually death.
Inheritance Information: GSD IV is autosomal recessive, meaning that animals with two copies of this allele will be affected. Animals with one copy of the gene will be clinically-normal carriers.
The possible genotypes are:
N/N The cat is normal, and cannot produce affected offspring.
N/gsdIV The cat is a carrier, and can pass the allele on to approximately 50% of any offspring. If bred to another N/gsdIV carrier, approximately 25% of the offspring will be normal, 50% will be carriers, and 25% will be affected.
gsdIV/gsdIV The cat is affected, and will not live long enough to reproduce.
– Carriers may be bred to normal animals (N/gsdIV x N/N) without any risk of producing affected offspring. The offspring should be tested before breeding to determine if they are carriers or normal.
– Breeding two carriers (N/gsdIV x N/gsdIV) is not recommended due to the possibility of 25% of the offspring being affected.
Test Information: This mutation test identifies a complex rearrangement in the GBE1 gene.
Fyfe, JC., Kurzhals, RL., Hawkins, MG., Wang, P., Yuhki, N., Giger, U., Van Winkle, TJ., Haskins, ME., Patterson, DF., Henthorn, PS.: A complex rearrangement in GBE1 causes both perinatal hypoglycemic collapse and late-juvenile-onset neuromuscular degeneration in glycogen storage disease type IV of Norwegian forest cats. Mol Genet Metab 90:383-92, 2007. Pubmed reference: 17257876. Doi: 10.1016/j.ymgme.2006.12.003.
Further information is available at the Online Mendelian Inheritance in Animals website.