Each August, the organization Families of Spinal Muscular Atrophy observe Spinal Muscular Atrophy (SMA) Awareness Month in order to help promote awareness of this disease that will hopefully one day lead to a cure. SMA is a motor neuron disease, which affects the voluntary muscles that are used for activities such as crawling, walking, head and neck control, and swallowing. It is a relatively common “rare” disorder affecting approximately one in 6,000 babies, and about one in 40 people are genetic carriers of the disease.
SMA affects muscles throughout the body, although the proximal muscles are often most severely affected. Proximal muscles are those closest to the trunk of the body – the shoulders, hips and back. Weakness in the legs is generally greater than in the arms and sometimes feeding and swallowing can be affected. Involvement of respiratory muscles – those involved in breathing and coughing – can lead to an increased tendency toward pneumonia and other lung problems.
There are four types of SMA – type I, II, III, and IV. The determination of the type of SMA is based on the physical milestones achieved. The first two types are diagnosed when the child is very young – as early as three months for Type I and 15 months for Type II. Type III is much more variable in age of onset, with diagnosis not occurring until adolescence in some cases. Type IV is also known as Adult Onset SMA because symptoms are not present until after age 35. It is rare for SMA to begin between ages 18 and 30, with Adult Onset SMA being much less common than the other three types.
Each type of SMA has variability among individual patients, which is important to remember when considering an individual’s care. Raising a child with SMA should be no different than raising a child who is not affected, but instead adapting age-appropriate activities for their level of ability. It is rare that SMA also affects a patient’s intellectual ability and it is often observed that patients with SMA are unusually bright and sociable.
For more information about SMA, please visit www.fsma.org