August is SMA Awareness Month
Updated: Oct 21, 2020
What is SMA?
Spinal muscular atrophy (SMA) is an inherited condition affecting the nerves of the spinal cord. Symptoms of SMA vary in severity, but damage to the spinal cord prevents the individual from moving, eating, and breathing normally. Sadly, SMA is thought to be the leading genetic cause of infant death.
How is SMA treated?
Although there is no cure for SMA, there are several FDA-approved therapies for SMA, and there are more clinical trials underway. Early diagnosis is important to achieving the best possible outcome.
What causes SMA?
SMA occurs when a person has two non-working copies of a gene important for the development of certain nerve cells in the spinal cord. Usually, each parent of a child with SMA is a carrier, which means that the person has one working copy and one non-working copy of the gene. If both parents are carriers and pass the non-working gene to the child, the child will have SMA. Because carriers of SMA are healthy, they may not have any family members with SMA and therefore have no idea that they could have a child with SMA.
How common is SMA?
In most populations, 1 in 40 to 1 in 60 individuals is a carrier for SMA. This translates to 1 in 6,000 to 1 in 10,000 live births. Carriers are thought to be less common in Latino populations.
What is carrier testing for SMA?
Carrier testing means that a healthy individual has a special DNA test to determine if he or she has a non-working copy of the SMA gene. If so, his or her partner can also be tested. If they are both carriers, then they have a 1 in 4 chance to have a child with SMA in each pregnancy.
Who should consider SMA carrier testing?
The American College of Obstetricians and Gynecologists recommends offering SMA carrier testing to all women who are considering pregnancy or already pregnant. Testing before pregnancy will mean that a woman and her partner will have more options, such as testing embryos through the IVF, using an egg or sperm donor, or adopting. Most important is to realize that early diagnosis is important to achieving the best outcomes. If you aren’t sure if genetic testing is for you, we recommend you review our free information guides to help you make your decision.
How do I request SMA carrier testing?
You may be able to arrange carrier testing through your health provider. However, not all health providers, even prenatal care providers, offer SMA carrier testing. If yours does not, you have other options. You can contact us at firstname.lastname@example.org for more information or visit our Family Screens page to get started. We won’t push you into testing; instead, we will help you decide if testing is right for you.
Carrier Screening for Genetic Conditions, Committee Opinion, American College of Obstetricians and Gynecologists. 2017. Accessed 7/29/2020 at https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2017/03/carrier-screening-for-genetic-conditions
CureSMA. Accessed 7/29/2020 at https://www.curesma.org/treatment/
FDA approves innovative gene therapy to treat pediatric patients with spinal muscular atrophy, a rare disease and leading genetic cause of infant mortality. FDA Press Release 5/24/2019. Accessed 8/2/2020 at https://www.fda.gov/news-events/press-announcements/fda-approves-innovative-gene-therapy-treat-pediatric-patients-spinal-muscular-atrophy-rare-disease
Wurster CD and Ludolph AC. Nusinersen for spinal muscular atrophy. Ther Adv Neurol Disord. 2018;11.