Amyotrophy is muscle or limb weakness and wasting. The two most common types are monomelic amyotrophy (MMA) and hereditary neuralgic amyotrophy (HNA). MMA occurs in upper limbs and is most common in Asia, while HNA is inherited and causes severe pain in the shoulder. Treatment focuses on managing symptoms.
Amyotrophy is weakness and wasting of muscles or limbs. There are many different conditions related to amyotrophy, but the two most common are monomelic amyotrophy (MMA) and hereditary neuralgic amyotrophy (HNA). These two conditions are similar in that they include wasting of a muscle or limb, but the HNA is usually concentrated in the shoulder and accompanied by severe pain. MMA also usually occurs in the upper limbs, but can also occur in the legs and is not accompanied by pain.
MMA has no clearly defined cause. The condition usually occurs in part of one of the patient’s upper limbs. The muscle will waste away, but this will happen gradually before reaching a period of stasis, in which the condition does not significantly worsen. There is a chance that the condition could spread to the limb from the other part of the body, but this usually doesn’t happen. MMA is most common in Asia, especially Japan and India. The condition typically affects males and is most likely to occur between the ages of 15 and 25.
The second disease, HNA, is known to be an inherited condition, meaning it is only likely to occur if the patient has a family history. The SEPT9 gene is known to be associated with the development of HNA, in approximately 85% of reported cases. If one of the patient’s parents has the condition, you have a 50/50 chance of developing the condition yourself. HNA initially manifests itself as extreme pain in the shoulder or upper arm, and after a couple of weeks, disuse atrophy will develop in the affected limb. The condition usually develops around the age of 28 and the patient will experience bouts of pain in the affected limb. These attacks will become less frequent as the patient ages.
Both MMA and HNA are conditions for which there is no cure, and treatment is usually geared towards making the patient’s life more manageable. With HNA, due to the severe pain usually associated with the condition, the primary focus of treatment is pain management. MMA treatment is more focused on strengthening the weak limb. Prevention is difficult in both conditions, although prenatal diagnosis of HNA is possible. This test is available to all parents who are at risk of passing the mutated gene on to their child.
Protect your devices with Threat Protection by NordVPN
