Spinal muscular atrophy (SMA) is a rare, inherited condition, the most common genetic cause of death among infants, for which there is no cure at present.
It is caused by a fault in the SMN1 gene (survival motor neuron 1), a gene necessary for the production of an important protein. This protein in responsible for basic motor functions like moving and breathing, and the lack of it causes the dying of nerve cells, a process that makes the connection between the brain and the muscles also end.
Both females and males can be affected, and the onset of the disease can vary from infancy to early adulthood.
There are four main types of SMA that vary in severity:
 SMA Type 1: The symptoms appear during the first months of life. Children are
unable to sit without help and usually do not survive their second birthday. Muscle
weakness does not come with mental deterioration.
 SMA Type 2: The symptoms appear between ages of 7 and 18 months. Life
expectancy is shortened, but treatments can improve most patients’ quality of life.
 SMA Type 3: The symptoms appear after the age of 18 months. Children are able to
stand and walk but usually lose their walking ability at a later stage of their lives. Life
expectancy is greatly is normal with this type.
 SMA Type 4: The symptoms appear in adulthood and the condition is not life
SMA affects approximately 1/10,000 infants, and the chance of being a carrier of the faulty gene is 1/35. If both parents are carriers, there is a 25% chance of having an offspring with SMA, 50% chance of our offspring becoming a carrier, and 25% chance of the offspring being healthy and a non-carrier.
How does the medication work? (An official and more detailed desciption of the drug is available online)
SMA is caused by a mutation of the SMN1 gene that carries the SMN protein (survival of motor neurons). This protein is key to the functioning of nerves that control our muscles. Without it, these nerves cease to function properly and eventually die.
There is, however, an identical protein made from the SMA2 gene, which can act as a substitute for the functioning of the SMA1. Unfortunately, the potency of these SMA2 proteins enables a mere 20% contribution towards the necessary tasks of the deficient gene, which is not sufficient to sustain life.
This is where the medication comes into play: it enables an increase in the creation of fully functioning proteins (from 20% to 60-70%), which leads to a significant improvement of the motor function, and therefore, an increased chance of survival. Studies of patients with an improved overall functioning are available through this link:

The medication is injected into the spinal canal and requires a strong team of medical professionals.