Pompe’s disease is a glycogen storage disorder. The conversion of glycogen to glucose is catalyses by the enzyme acid alpha-glycosidase. A defect in the function of this enzyme causes a build-up of glycogen leading to muscle weakness throughout the body including the heart. The average life expecting of an affected calf is less than 12 months and should be culled.
Pompe’s disease is an autosomal recessive disorder. Carriers of the disease are unaffected and perform normally. Crossing two carriers of Pompe’s results in a 25% chance for an affected progeny. It is therefore important to know the status of all animals to be used for breeding purposes in a stud. This information can then be used when taking breeding decisions
Autosomal recessive inheritance is characterized by the following:
- The defective gene must be transmitted from BOTH parents to produce an affected offspring.
- Both parents must be carriers (heterozygous) for the disorder to produce an affected offspring.
- A carrier (heterozygate) produces either normal progeny of affected progeny when two (2) carriers are crossed.
- Unaffected (non-carrier) parents can only produce normal offspring.
- If the offspring of a cross between two carriers is proven to be normal (no defective gene for CMS) the possibility of the disorder manifesting ends in this progeny
Purely from a scientific point of view advice would be the following:
Do line breeding and crossing with animals that are non-carriers of Pompe’s or cross a carrier animal with a non-carrier.
- If crossings are allowed between carriers and non-carriers confirm the status of the offspring for future breeding purposes.
It is important to note that carriers for Pompe’s “ormal”animals, which have the same performance as non-carrier “normal”animals.