CHRNA1-related congenital myasthenic syndrome
Type of disease: Rare conditions
CHRNA1-related congenital myasthenic syndrome is a genetic disorder that causes muscle weakness in the limbs, face, eyes and throat. The syndrome is usually identified in infancy, with the muscle weakness causing poor feeding, swallowing and weak cries. In rare cases, the syndrome is not evident until childhood when the condition causes difficulty running, and extreme exercise-induced fatigue. Syndrome symptoms may be induced by fever, infection, excitement and exercise. Rare cases of the syndrome are associated with respiratory disease. There are many types of congenital myasthenic syndrome, all sharing similar symptoms. CHRNA-1 refers to the gene mutation that causes this particular variant of the syndrome. The mutation disrupts brain-to-muscle communication by reducing the amount, or reducing the effectiveness, of certain brain receptors used to detect muscle signals. The syndrome is usually inherited as an autosomal recessive trait (an affected gene is inherited from both parents). An exception is the slow-channel syndrome variant, which is inherited as an autosomal dominant trait (only one affected gene needed to cause the condition).