SNP Shot: Genomic Insights

Actin-accumulation myopathy is a condition impacting primarily the skeletal muscles, those responsible for body movement. Individuals affected by this myopathy experience significant muscle weakness (myopathy) and reduced muscle tone (hypotonia) throughout their bodies. The condition's signs and symptoms manifest early in infancy, including challenges with feeding and swallowing, a faint cry, and impaired head control. Infants with this condition are often described as "floppy" and may lack the ability to move independently.

The pronounced muscle weakness associated with actin-accumulation myopathy extends to the muscles essential for respiration. Individuals with this condition may exhibit shallow breathing (hypoventilation), particularly during sleep, leading to oxygen deprivation and carbon dioxide retention in the bloodstream. Recurring respiratory infections and life-threatening breathing complications are common. Due to these respiratory issues, the majority of affected individuals do not survive beyond infancy. Those who do survive experience delays in motor skill development, such as sitting, crawling, standing, and walking.

The term "actin-accumulation myopathy" stems from the distinctive accumulation of actin protein filaments within muscle cells. These accumulations are visible under microscopic examination of muscle tissue.

Inheritance:

Actin-accumulation myopathy is classified as an autosomal dominant disorder. This means that only one copy of the mutated gene within each cell is enough to cause the condition. In most instances, the condition is not inherited. Rather, it arises from new (de novo) mutations in the gene, occurring in individuals with no prior family history of the disorder.