spinal muscular atrophy

Also known as spinal muscle atrophy, survival motor neuron spinal muscular atrophy, spinal muscular atrophies of childhood, SMA, 5q SMA

rare congenital neuromuscular disorder

Key facts

Other names: Autosomal recessive proximal spinal muscular atrophy, 5q spinal muscular atrophy
Specialty: Neurology
Symptoms: Progressive muscle weakness
Complications: Scoliosis , joint contractures , pneumonia
Usual onset: Mutation is congenital; symptom start varies by type
Duration: Lifelong
Types: Type 0 to type 4
Causes: Mutation in SMN1
Diagnostic method: Genetic testing
Differential diagnosis: Congenital muscular dystrophy , Duchenne muscular dystrophy , Prader-Willi syndrome
Treatment: Supportive care , medications
Medication

Article

Spinal muscular atrophy (SMA) is a rare neuromuscular disorder that results in the loss of motor neurons and progressive muscle wasting. It is usually diagnosed in infancy or early childhood and if left untreated it is the most common genetic cause of infant death. It may also appear later in life and then have a milder course of the disease. The common feature is the progressive weakness of voluntary muscles, with the arm, leg, and respiratory muscles being affected first. Associated problems may include poor head control, difficulties swallowing, scoliosis, and joint contractures.

The age of onset and the severity of symptoms form the basis of the traditional classification of spinal muscular atrophy into several types.