Alpha-Mannosidosis Results on Genex Sires

Alpha-Mannosidosis
Although, Alpha-Mannosidosis (MA) is one of the oldest known genetic defects to be identified in Angus and Angus-derived cattle, awareness of the defect has been very limited among cattle producers. The knowledge of MA is largely due to the efforts of Angus Australia, as they met an MA outbreak head-on and have since essentially eradicated the defect from their population. That eradication process was initiated in 1980 as the result of several Australian animals being diagnosed with MA. The development of a DNA test for MA in 1997 provided Angus Australia with an accurate tool for identification of carrier animals. Although Australia has the most experience with MA, it has been documented in other countries, including an American case in the late 1970s. In a preemptive move to prevent MA from having a large impact on the American Red Angus population, the DNA test for MA is now available in the United States.

What is Alpha-Mannosidosis?
Alpha-Mannosidosis is an inherited and lethal lysosomal storage disease of Aberdeen Angus cattle. Affected calves are born alive with no physical deformities. Prior to reaching sexual maturity, affected animals show severe, progressive neurological disease characterized by tremors of the head, loss of muscle coordination, and aggression when disturbed. The net effect is eventual death.

What is the inheritance pattern of Alpha-Mannosidosis?
Identical to other genetic defects monitored by RAAA, the inheritance of MA is classified as a simple recessive. Thus, only animals possessing two copies of the MA mutation will exhibit the genetic defect. Carrier animals (those animals possessing one copy of the MA mutation) will appear normal, but when mated to another carrier animal will produce a MA affected animal 25% of the time.