Event Series: Spinal Muscular Atrophy Awareness Month

Spinal Muscular Atrophy Awareness Month

August 2, 2029

Spinal Muscular Atrophy Awareness Month

August is Spinal Muscular Atrophy Awareness Month. SMA is a genetic disorder that starts in the central nervous system (CNS) and affects all the muscles in the body. Due to the degenerative nature of the disease, people with SMA experience a decline in muscle strength over time. The rate and severity can vary among individuals.

Whether you have SMA, a loved one with SMA, are a researcher, care provider, industry partner, or are new to the SMA community, SMA Awareness Month is a time to come together to celebrate, honor, reflect, remember, and learn. From local events to national advocacy, there are plenty of ways for you to get involved and help lead the charge. Wear a cream enamel awareness ribbon pin, cream fabric ribbon, or cream awareness silicone wristband bracelet.

About SMA and Spinal Muscular Atrophy Awareness Month

Spinal muscular atrophy (SMA) is a progressive neurodegenerative disease that affects the motor nerve cells in the spinal cord. This impacts the muscles used for activities such as breathing, eating, crawling, and walking. Each year, thousands of infants in the U.S. and around the world are born with SMA. SMA also impacts children, teens, and adults from every background, race, and gender. Approximately one in 50 people, more than six million total, is a genetic carrier for SMA. There are several approved treatments for SMA. But, we do not yet have a cure.

Describing Spinal Muscular Atrophy

No two people with spinal muscular atrophy (SMA) have identical experiences. Decisions about care and treatment are made according to each individual’s needs.

The History of Describing SMA and Spinal Atrophy Awareness Month

Historically, and prior to disease modifying treatment being available, SMA was characterized and divided into five types of SMA: Types 0, 1, 2, 3, and 4. This historical description by type of SMA is based on the age that symptoms began. It also considers the highest physical milestone achieved. Within each type, abilities can vary from person to person.

In addition, individuals with SMA frequently lost function over time due to loss of motor nerves and muscles continuing to weaken. This classification system describing age of onset and maximum motor function continues to apply to adults, teens, and some children with SMA.

How Do We Classify SMA Today?

Generally, we know that the number of SMN2 gene copies (the back-up gene for SMN1) a person has impacts the severity of SMA. Having more copies of SMN2 is associated with less severe symptoms of SMA. Following the approval of the first disease modifying treatment for SMA in 2016 (an SMN enhancing therapy) and the implementation of newborn screening for SMA in 2018, the historical classification of SMA does not adequately describe the new generation of infants and children with SMA treated early in life. In addition, more infants are being diagnosed and receive treatment prior to the onset of symptoms. With treatment, individuals are gaining more physical milestones and abilities than history would predict.

The SMA community of healthcare providers, people with SMA, and their families are having many conversations about how to best describe SMA disease in the era of disease modifying SMA treatment.

Characteristics that have risen to the top and that are generally used together include:

SMN2 copy number (SMN2 is an important disease modifying gene).
Maximum motor function achieved, for example non-sitter, sitter, and walker.
Age of symptom onset.
Impact of symptoms or the severity of symptoms.
Age at first treatment.

Historical Classification of SMA Prior to Treatments:

Most Applicable To Older Children and Adults With SMA:

TYPE 0

SMA Type 0 is very rare and very severe. Symptoms begin prior to birth and are seen as decreased fetal movement in the weeks prior to delivery. At birth, the infant has severe weakness and often difficulty breathing and feeding and may have joint contracture and heart problems. These infants typically require breathing and feeding support prior to confirming the diagnosis. These infants historically survived a few months.
TYPE 1

Also known as Werdnig-Hoffmann disease, SMA Type 1 is the most common (60%) and a severe form, usually diagnosed during an infant’s first six months. Babies with SMA Type 1 face many physical challenges, including muscle weakness and trouble breathing, coughing, and swallowing. Historically they often needed breathing assistance and a feeding tube. If not treated, Type 1 can be fatal early on in life.
TYPE 2

Type 2 is usually diagnosed after six months of age, but before two years of age. The first sign is often a delay in meeting motor milestones or failing to meet milestones entirely. Individuals with SMA Type 2 can typically sit up without help, though they may need assistance getting into a seated position. Historically, they are unable to walk and will require a wheelchair.
TYPE 3

Also called Kugelberg-Welander disease or juvenile SMA, Type 3 is usually diagnosed after 18 months of age and before three years of age. However, SMA Type 3 can be diagnosed as late as the teenage years. Individuals with SMA Type 3 are initially able to walk and historically have increasingly limited mobility as they grow, and eventually, many need to use a wheelchair.
TYPE 4

SMA Type 4 is very rare. It is diagnosed in less than 1% of all cases. It usually surfaces in adulthood, and leads to mild motor impairment. While symptoms can begin as early as age 18 years, they often begin after age 35 years.