Glycogen storage disease type IV / GSD IV (GBE1-related) - Norwegian Forest Cat

Glycogen storage disease type IV in Norwegian Forest Cats

This DNA test analyses the GBE1 rearrangement variant that causes glycogen storage disease type IV in Norwegian Forest Cats. The condition is also known as GSD IV or glycogen branching enzyme deficiency. GBE1 encodes glycogen branching enzyme, which is needed to build and store glycogen normally.

When both gene copies carry the tested variant, abnormal glycogen is formed and especially muscle and nerve function can be damaged. Affected kittens may be stillborn or develop severe weakness, tremors, muscle problems, fever episodes, delayed growth or progressive neurological decline early in life.

Practical value of this test

• Determines whether a Norwegian Forest Cat is clear, a carrier or genetically affected for the tested GBE1 variant.
• Helps breeders identify carriers reliably before breeding combinations are planned.
• Supports avoidance of matings where kittens could inherit two copies of this severe recessive variant.

GSD IV follows an autosomal recessive mode of inheritance. Carriers are usually healthy themselves, but two carriers can produce affected offspring.