Spinal muscular atrophies (SMAs)
Causes and risk factors
The classic form of SMA is caused by a defect in one of two genes, SMN1 and SMN2, which results in insufficient levels of a protein called SMN. The mode of transmission is autosomal recessive: parents are healthy carriers of the genetic defect and have a 25% chance of transmitting the disease to each of their children.
Only a few genes of adult and distal forms are known.
How is it diagnosed?
Diagnostic suspicion is based on very characteristic clinical signs and often on electromyography, which shows signs of neurogenic distress. Diagnostic confirmation is obtained by genetic analysis.
How is it treated?
There is no definitive cure at this time, but numerous studies are underway to evaluate possible therapies that work at the genetic level or in an attempt to prevent motor neuron loss.