A brief overview of the 4 types of SMA
A rare genetic condition, spinal muscular atrophy (SMA), affects one in six to ten thousand people. This condition causes an impairment in the individual’s ability to control their muscle movement. The main cause of the condition is a gene mutation; however, the symptoms, onset, and progress of the condition can be significantly different in every case. This is why SMA is broadly divided into four different types to provide information for physicians. Following is information about the four types of SMA for physicians: Type 1 SMA – Type 1 SMA is also referred to as infantile-onset SMA or Werdnig-Hoffmann disease. The main cause of this condition is possession of only two copies of the SMN2 gene. This is the most common type of SMA and more than half the patients are diagnosed with the type 1 SMA. The symptoms for this type start within the first six months of birth. They include weak cries; difficulty in moving, swallowing, or breathing; hypotonia (weak or floppy arms and legs); and inability to sit without support. Babies usually did not survive type 1 SMA, but with more information on SMA for physicians with new research and technology, a drastic change in the survival rate has been noted.