IBBA IBBA CONNECTION CONNECTION // // POMPES POMPES DISEASE DISEASE
POMPES Disease Genetic Conditions: PD
by IBBA Member Relations Coordinator & DNA Specialist Macee Prause Have you had calves born alive but die prior to weaning or less than a year of age? Have you ever had a young animal trying to get off the ground but continue to lie on its side paddling? Have you found one of your Brangus® that has died after physically challenging terrain or from what appears to be a heart attack? It is possible that those animals were genetically affected for Pompes disease (PD). Pompes disease is an inherited, autosomal recessive genetic condition. PD is a neuromuscular disease that can be genetically identified as: a two base pair SNP deletion known as the E7 mutation found in Brahman and Brahman-influenced cattle; a nonsense mutation known as the E13 mutation found in Brahman and Brahman-influenced cattle; or a two base pair SNP deletion known as the E18 mutation more commonly found in Shorthorns or Shorthorn-influenced cattle. All three mutations are due to deficiency in essential activity acidic α-glucosidase (AAG). The result of this deficiency causes glycogen to accumulate inside of muscle and nerve cells. This buildup of glycogen interferes with normal tissue function initiating progressive muscular weakness, uncoordinated gaits and a decreased life expectancy. There are some physical signs that Pompes affected individuals exhibit, but these symptoms vary by individual because all muscle groups are affected yet one tissue group may be most affected. The most common symptom in Pompes affected animals is progressive muscular weakness due to compromised muscle function. Since the disease is progressive, the symptoms are more noticeable during stressful events such as weaning or inadequate nutrition. During the final stages of the disease’s progression, calves can be found paddling on their sides, suffer heart attacks from the glycogen build up in their heart, become blind due to nervous system interference, or have fallen down a treacherous terrain. A majority of Pompes disease affected individuals die before they reach breeding age, typically less than a year of age; therefore, their affected disease status does not propagate to future progeny. For Brangus cattle, the E7 and E13 mutations would be tested to determine Pompes status with the E7 mutation being the more common instigator. Many labs that use 50K SNP testing have access to the Pompes mutation test as this is built as an add-on of the 50K SNP chip. It is important to know the Pompes status of your animals if you plan to export semen and/or embryos to countries such as South Africa and Australia. These are two of the countries that mandate Pompes status checks prior to heavy influences of a single genetic line. As this trait is a recessively inherited disease, carrier animals appear normal. It isn’t until carrier animals get to breeding age and have affected progeny die prior to weaning age that this trait is considered. By then, the carrier status might have affected the entire herd if it was a heavily used sire, AI sire or ET donor dam. For more information regarding DNA genetic condition testing, making DNA requests and the Pompes disease testing, please contact Macee Prause in IBBA’s office at (210) 696-8231 or by email at mprause@gobrangus.com.
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// MARCH 2019