Spinal Muscular Atrophy (SMA) is a condition that you may not have heard of, but it is the number one genetic cause of death in infancy. [1] SMA can onset at any age, and is staged by the age and functional ability of a person at onset of the disease. [1] While only 1 in 11,000 babies are born with SMA, 1 in 50 Americans are genetic carriers of the disease, though do not have symptoms of spinal muscular atrophy. [1]