Distal spinal muscular atrophy, also known as distal hereditary motor neuropathy (dHMN), is a rare genetic disorder characterized by the degeneration of motor neurons in the spinal cord. It primarily affects the muscles in the distal parts of the limbs, such as the hands, feet, and lower legs, leading to weakness and muscle wasting.
This condition is typically inherited in an autosomal dominant manner, meaning that an affected individual has a 50% chance of passing the genetic mutation to their offspring. However, it can also be inherited in an autosomal recessive pattern.
Distal spinal muscular atrophy is categorized into several types based on the specific gene mutations involved, and the age of onset and severity of symptoms can vary. Common symptoms include difficulty with tasks requiring fine motor skills, such as writing or buttoning a shirt, muscle cramps, and progressive weakness. Over time, the weakness can advance to affect the proximal muscles as well.
Diagnosis is established through clinical evaluations, electromyography (EMG), nerve conduction studies, and genetic testing to identify the specific gene mutation responsible for the condition. Unfortunately, there is currently no cure for distal spinal muscular atrophy, so treatment focuses on managing symptoms and improving quality of life. This may involve physical and occupational therapy, assistive devices to aid in mobility or daily activities, pain management, and genetic counseling for affected individuals and their families.
