Spinal muscular atrophy with lower extremity predominance 1

Spinal muscular atrophy with lower extremity predominance 1 (SMALED1) is an extremely rare neuromuscular disorder of infants characterised by severe progressive muscle atrophy which is especially prominent in legs.^[1]

Spinal muscular atrophy with lower extremity predominance 1
Other names	Lower extremity predominant spinal muscular atrophy type 1, SMALED1
Spinal muscular atrophy with lower extremity predominance is inherited in an autosomal dominant manner.
Specialty	Neurology
Symptoms	Progressive muscle atrophy in legs
Usual onset	Infancy
Causes	Mutation in DYNC1H1 gene
Diagnostic method	Molecular test

The disorder is associated with a genetic mutation in the DYNC1H1 gene (the gene responsible also for one of the axonal types of Charcot–Marie–Tooth disease)^[2][3] and is inherited in an autosomal dominant manner. As with many genetic disorders, there is no known cure to SMALED1.^{[citation needed]}

The condition was first described in a multi-generational family by Walter Timme in 1917.^[4] Its linkage to the DYNC1H1 gene was discovered in 2010 by M. B. Harms, et al., who also proposed the current name of the disorder.^[1][5]

See also

• Spinal muscular atrophies
• Spinal muscular atrophy with lower extremity predominance 2A
• Spinal muscular atrophy with lower extremity predominance 2B