SNP Shot: Genomic Insights

Potassium-aggravated myotonia is a condition impacting skeletal muscles, the muscles responsible for movement. Individuals with this disorder typically begin experiencing episodes of prolonged muscle tension (myotonia) in childhood or adolescence, making it difficult for their muscles to relax. This myotonia leads to muscle stiffness that intensifies after physical activity. A key characteristic of this condition is that episodes of myotonia can be triggered or worsened by consuming potassium-rich foods, like bananas and potatoes. These episodes result in stiffness affecting skeletal muscles throughout the body.

The severity of potassium-aggravated myotonia varies, ranging from mild and fluctuating muscle stiffness (myotonia fluctuans) to a severe and debilitating form with frequent attacks (myotonia permanens). Notably, unlike certain other types of myotonia, potassium-aggravated myotonia does not involve episodes of muscle weakness.

Inheritance:

Potassium-aggravated myotonia follows an autosomal dominant inheritance pattern. This means that having just one copy of the mutated gene in each cell is enough to cause the disorder. In some instances, an individual with potassium-aggravated myotonia inherits a variation in the SCN4A gene from an affected parent. In other instances, the condition arises from a new gene mutation. These new mutations can occur in individuals with no prior family history of the disorder.