About SMA

What is spinal muscular atrophy?

Spinal muscular atrophy is a rare degenerative problem that affects the spinal cord and nerves, resulting in muscle wasting and weakness

What causes spinal muscular atrophy?

SMA is an autosomal recessive disease. This means that both males and females are equally affected, and that two copies of the gene, one inherited from each parent, are necessary to have the condition.

A gene called survival motor neuron (or SMN) is found to have an abnormal area (either a deletion or extra copy of the gene) in over 95 percent of cases of SMA. Symptomatic individuals of all ages can be tested through DNA studies typically done from a blood sample.

When both parents are carriers, there is a one in four, or 25 percent, chance, with each pregnancy, to have a child with SMA. Carrier testing for the general population is technically difficult and usually available only if a previously affected child in the family has been studied.

What are the symptoms of spinal muscular atrophy?

Spinal muscular atrophy is sometimes difficult to diagnose, as symptoms can resemble other conditions or medical problems. Each child may experience symptoms differently. There are four types of spinal muscular atrophy based on symptoms and age of onset. The child may have the following symptoms:

  • Type I (Also called Werdnig-Hoffman.)
    This is the most severe type of SMA and may be present at birth. Infants have problems holding their head, sucking, feeding, swallowing, and typically move very little. The muscles of the chest are also affected. The motion of the tongue is described as having “worm-like” movements. Death results usually by the age of two to six years from breathing problems.
  • Type II (intermediate form) 
    This form of SMA is seen in children from seven months to 18 months of age. They typically have generalized muscle weakness and may require braces, walkers, or a wheelchair for assistance. Life-expectancy may extend to the 20s and 30s.
  • Type III (Also called Wohlfart-Kugelberg-Welander.)
    This form of SMA affects children older than 18 months of age. These children show signs of clumsiness, difficulty walking, mild muscle weakness, and may be developmentally delayed. These children live long into their adult years.
  • Type IV
    This form of SMA affects adults in their 30s and 40s, causing problems in walking.

For further information on Spinal Muscular Atrophy go to:

The Leah Reilly Foundation was set up by Greg and Cara Reilly to help and support other families in South Africa living with SMA. They lost their 19 month old daughter to SMA.

Families of SMA, this is an international site raising money towards SMA research.