What is Spinal Muscular Atrophy?

Spinal muscular atrophy (SMA) is a rare inherited neuromuscular condition, of which there are several distinct types. The condition may affect crawling and walking ability, arm, hand, head and neck movement, breathing and swallowing.

There are four main types of SMA which are caused by a fault in the gene called Survival Motor Neuron 1 (SMN1). This gene carries the information required for the production of an important protein. When there is not enough of this protein, the nerve cells that help to control the muscles for moving and breathing become damaged.

The four main types of SMA vary greatly in severity:

The effects of each type of SMA vary greatly between individuals. Life expectancy varies between and within the different types of SMA.

In order to treat SMA, the underlying genetic defect needs to be addressed. At present this is not possible. The day-to-day focus is therefore on treatment of the symptoms and the delivery of the highest standards of care. This includes anticipatory care, managing symptoms and maintaining the best quality of life.

How many people are affected?

How do people get SMA?

What research is taking place?

There is extensive work taking place on the genetics of SMA which aims to improve our understanding of the disease mechanisms leading to damage of the nerve cells.

Improved understanding of the condition has led to the development of potential treatments with the aim of restoring the production of SMN protein in the nerve cells. Some of these potential treatments are already being tested in clinical trials.

There is considerable cutting-edge SMA research taking place internationally, with many effective collaborations. Several Centres are involved in clinical trials and research into potential treatments.

For more information about the different types of SMA, visit: www.smasupportuk.org.uk/information-support



  1. Montes, J., Gordon, A.M., Pandya, S., De Vivo, D.C. and Kaufmann, P. (2009) ‘Clinical outcome measures in spinal muscular atrophy’,Journal of Child Neurology, 24(8), pp. 968-978.
  2. Standards of Care for SMA: A Family Guide.
  3. Wang, C.H., Finkel, R.S., Bertini, E.S., Schroth, M., Simonds, A., Wong, B., Aloysius, A., Morrison, L., Main, M., Crawford, T.O. and Trela, A. (2007) ‘Consensus statement for standard of care in spinal muscular atrophy’, Journal of Child Neurology, 22(8), pp. 1027-49.