Spinal muscular atrophy (SMA) is a rare genetic disorder that causes weakness. It affects motor neurons in the spinal cord, resulting in weakness of the muscles used for movement. In most cases of SMA, signs and symptoms are present at birth or appear within the first 2 years of life.
If your baby has SMA, it will limit their muscle strength and their ability to move. Your baby may also have difficulty breathing, swallowing, and feeding.
Take a moment to learn about how SMA may affect your child, as well as some of the treatment options that are available to manage this condition.
SMA is classified into five types, based on the age when symptoms appear and the severity of the condition. All types of SMA are progressive, which means they tend to get worse over time.
Type 0
Type 0 SMA is the rarest and most severe type.
When a baby has type 0 SMA, the condition may be detected before they’re born, while they’re still developing in the womb.
Babies born with type 0 SMA have extremely weak muscles, including weak respiratory muscles. They often have trouble breathing.
Most infants born with type 0 SMA don’t survive for more than 6 months.
Type 1
Type 1 SMA is also known as Werdnig-Hoffmann disease or infantile-onset SMA. It’s the most common type of SMA, according to the National Institutes of Health (NIH).
When a baby has type 1 SMA, they will likely show signs and symptoms of the condition at birth or within 6 months of being born.
Children with type 1 SMA typically can’t control their head movements, roll over, or sit without help. Your child may also have difficulty sucking or swallowing.
Children with type 1 SMA also tend to have weak respiratory muscles and abnormally shaped chests. This can cause serious breathing difficulties.
Many children with this type of SMA don’t survive past early childhood. However, new targeted therapies may help improve the outlook for children with this condition.
Type 2
Type 2 SMA is also known as Dubowitz disease or intermediate SMA.
If your baby has type 2 SMA, signs and symptoms of the condition will likely appear between the ages of 6 and 18 months.
Children with type 2 SMA typically learn to sit on their own. However, their muscle strength and motor skills tend to decline over time. Eventually, they often need more support to sit.
Children with this type of SMA typically can’t learn to stand or walk without support. They often develop other symptoms or complications as well, such as tremors in their hands, unusual curvature of their spine, and breathing difficulties.
Many children with type 2 SMA survive into their 20s or 30s.
Types 3 and 4
In some cases, babies are born with types of SMA that don’t produce noticeable symptoms until later in life.
Type 3 SMA is also known as Kugelberg-Welander disease or mild SMA. It typically appears after 18 months of age.
Type 4 SMA is also called adolescent- or adult-onset SMA. It appears after childhood and tends to cause only mild to moderate symptoms.
Children and adults with type 3 or type 4 SMA may experience difficulties with walking or other movements, but they tend to have normal life expectancies.
SMA is caused by mutations in the SMN1 gene. The type and severity of the condition is also affected by the number and copies of the SMN2 gene that a baby has.
To develop SMA, your baby must have two affected copies of the SMN1 gene. In most cases, babies inherit one affected copy of the gene from each parent.
The SMN1 and SMN2 genes give instructions to the body for how to produce a type of protein known as the survival motor neuron (SMN) protein. SMN protein is essential to the health of motor neurons, a type of nerve cell that passes signals from the brain and spinal cord to muscles.
If your baby has SMA, their body is unable to produce SMN proteins properly. This causes motor neurons in their body die. As a result, their body can’t properly send motor signals from their spinal cord to their muscles, which leads to muscle weakness, and eventually causes muscle wasting due to lack of use.
If your baby shows signs or symptoms of SMA, their doctor can order genetic testing to check for the genetic mutations that cause the condition. This will help their doctor learn if your child’s symptoms are caused by SMA or another disorder.
In some cases, the genetic mutations that cause this condition are found before symptoms develop. If you or your partner has a family history of SMA, your doctor might recommend genetic testing for your child, even if your child appears healthy. If your child tests positive for the genetic mutations, their doctor may recommend starting immediate treatment for SMA.
In addition to genetic testing, your doctor might order a muscle biopsy to check your child’s muscle for signs of muscle disease. They might also order an electromyogram (EMG), a test that allows them to measure the electrical activity of muscles.
There is currently no known cure for SMA. However, multiple treatments are available to help slow the progression of the disease, relieve symptoms, and manage potential complications.
To provide the support that your baby needs, their doctor should help you assemble a multidisciplinary team of healthcare professionals. Regular checkups with members of this team are essential for managing your child’s condition.
As part of their recommended treatment plan, your child’s health team may recommend one or more of the following:
- Targeted therapy. To help slow or limit the progression of SMA, your child’s doctor may prescribe and administer the injectable medications nusinersen (Spinraza) or onasemnogene abeparvovec-xioi (Zolgensma). These medications target underlying causes of the disease.
- Respiratory therapy. To help your baby breathe, their health team may prescribe chest physiotherapy, mechanical ventilation, or other respiratory treatments.
- Nutritional therapy. To help your baby get the nutrients and calories they need to grow, their doctor or dietitian may recommend nutritional supplements or tube feeding.
- Muscle and joint therapy. To help stretch their muscles and joints, your child’s health team may prescribe physical therapy exercises. They may also recommend the use of splints, braces, or other devices to support healthy posture and joint positioning.
- Medications. To treat gastroesophageal reflux, constipation, or other potential complications of SMA, your child’s health team may prescribe one or more medications.
As your child gets older, their treatment needs will likely change. For example, if they have severe spinal or hip deformities, they may need surgery in later childhood or adulthood.
If you’re finding it emotionally difficult to cope with your baby’s condition, let your doctor know. They may recommend counseling or other support services.
Your baby’s physical therapist, occupational therapist, or other members of their health team may encourage you to invest in special equipment to help care for them.
For example, they may recommend:
- light-weight toys
- special bath equipment
- adapted cribs and strollers
- molded pillows or other seating systems and postural supports
If anyone in your family or your partner’s family has SMA, your doctor may encourage you and your partner to undergo genetic counseling.
If you’re thinking about having a baby, a genetic counselor can help you and your partner assess and understand your chances of having a child with SMA.
If you already have a child with SMA, a genetic counselor can help you assess and understand the chances that you will have another child with this condition.
If you have multiple children and one of them is diagnosed with SMA, it’s possible that their siblings may also carry the affected genes. A sibling might also have the disease but not be showing noticeable symptoms.
If your doctor believes that any of your children are at risk of having SMA, they can order genetic testing. Early diagnosis and treatment may help improve your child’s long-term outlook.
If your child has SMA, it’s important to get help from a multidisciplinary team of healthcare professionals. They can help you understand your child’s condition and treatment options.
Depending on your child’s condition, their health team may recommend treatment with a targeted therapy. They may also recommend other treatments or lifestyle modifications to help manage the symptoms and potential complications of SMA.
If you’re finding it difficult to cope with the challenges of caring for a child with SMA, let your doctor know. They can refer you to a counselor, support group, or other sources of support. Having the emotional support that you need can enable you to better care for your family.
FAQs
Can babies with SMA walk? ›
Depending on the severity of symptoms, children with type 2 may have a normal life span. Type 3 is a milder form of SMA. It's also known as Kugelberg-Welander disease and resembles muscular dystrophy. While children with type 3 usually are able to walk, most have some difficulty walking.
Can babies with SMA roll over? ›Children with type 1 SMA typically can't control their head movements, roll over, or sit without help. Your child may also have difficulty sucking or swallowing.
What percentage of babies are born with SMA? ›One in every 6,000 babies is born with SMA. It occurs in both males and females of all races, and can begin in infancy, childhood, or adulthood, three of which affect children.
What are the reasons for SMA in babies? ›How SMA is inherited. In most cases, a child can only be born with SMA if both of their parents have a faulty gene that causes the condition. The parents will not usually have SMA themselves, which is known as being a carrier. Around 1 in every 40 to 60 people is a carrier of the main faulty gene that causes SMA.
What does a baby with SMA look like? ›The signs of SMA can vary. Some babies with SMA are "floppy" and don't learn to roll or sit at the expected age. An older child might fall more often than kids of the same age or have trouble lifting things. Kids with SMA can develop scoliosis (a curved spine) if the back muscles are weak.
How do you feed a baby with SMA? ›- Pull the safety seal and open the lid. The scoop is provided under the lid. ...
- Wash hands well. ...
- Boil 1 litre of fresh tap water. ...
- Strictly follow the feeding table. ...
- Place the sterilised teat and cap on the bottle and shake well until powder is fully dissolved.
If only one parent is a carrier, the child is usually not at risk for SMA, though the child does have a 50% chance of also being a carrier themselves. In rare cases, spontaneous genetic changes in the SMN1 gene can occur during egg or sperm production. In this situation, only one parent will be a carrier.
Is SMA more common in males or females? ›Results. 58.02% of patients with a SMA diagnosis were males while 40.84% were females. Average age of diagnosis was 38.31 ± 24.49 years ±SD. Significantly lower was the age of diagnosis of spinal muscular atrophy type I, 1.81 ± 3.01 years.
Can SMA be detected during pregnancy? ›If you're pregnant and there's a risk you could have a child with SMA, tests can be carried out to check for the condition. The 2 main tests are: chorionic villus sampling (CVS) – a sample of cells from the placenta are tested, usually during weeks 11 to 14 of pregnancy.
How common is SMA in the USA? ›Spinal Muscular Atrophy (SMA) is a genetic disorder that affects approximately 1 out of every 10,000 people.
Who carries the SMA gene? ›
What does it mean to be a carrier of spinal muscular atrophy? A carrier is a person who inherits one healthy copy and one faulty copy of the SMN1 gene. About 1 in 40 to 1 in 60 people are carriers of SMA. If both parents are carriers, they have a 1-in-4 chance of having a child with SMA.
How long does a baby live with SMA? ›Infants with type 1 SMA usually die before their second birthday. Children with type 2 or type 3 SMA may live full lives depending on the severity of symptoms. People who develop SMA during adulthood (type 4) often remain active and enjoy a normal life expectancy.
What causes death in SMA? ›Complications of infantile spinal muscular atrophy
Children and adults with SMA are prone to respiratory infections. In the more severe types of SMA, respiratory infections such as pneumonia are often the cause of death.
Spinal muscular atrophy (SMA) is one of the most common genetic conditions that affect children. One in every 6,000 to 10,000 babies worldwide are born with SMA. Type 1 SMA is the most severe type and accounts for more than half of all cases.
Is SMA a birth defect? ›Spinal muscular atrophy type 0 is evident before birth and is the rarest and most severe form of the condition. Affected infants move less in the womb, and as a result they are often born with joint deformities (contractures). They have extremely weak muscle tone (hypotonia) at birth.
Who has lived the longest with SMA type 1? ›For nearly 15 years, Steve Mikita, one of the oldest living people with spinal muscular atrophy (SMA), has brought the patient voice to the forefront of rare disease research. Steve's journey for improving patient education and experiences started early in his life. “When I was 12, I had a spinal fusion operation.
How do you know if you carry the gene for SMA? ›Carrier testing is available through a simple blood test. The test can detect the most common mutation that is associated with SMA and will detect approximately 90 percent of carriers. A negative carrier test will greatly reduce the likelihood of having a child affected with this condition.
Can you put SMA in the fridge? ›SMA® PRO First Infant Milk
200 ml on-the-go resealable cartons are easy to pour and can be kept in the fridge for up to 24 hours after opening.
SCIENCE INSPIRED BY NATURE. SMA® Extra Hungry Infant Milk is a nutritionally complete* breast milk substitute for hungrier bottle fed babies, which may help delay early weaning until the recommended time. It is enriched with Omega 3 (DHA)** and can be used to combination feed.
Is SMA good newborn? ›SMA® Nutrition products for babies 0-6 months
Breastfeeding provides the best start for your baby, but if you decide to combination feed or bottle-feed then our range of First Infant Milks are nutritionally complete* breast milk substitutes, suitable from birth.
What is a silent carrier of SMA? ›
A silent carrier is an individual who has 2 SMN1 copies in cis, and current technologies are unable to detect because it cannot identify the haplotype phase. Therefore, the residual risk for carrier statis is higher upon a negative carrier screen or a carrier screening result identifying 2 copies of SMN1.”
Can people with SMA have kids? ›Adults with SMA can still have children and start families with their partners. Talk to a genetic counselor about the risk of future children having or carrying SMA. They can help you prepare for all possible situations.
Is SMA always inherited? ›Except in rare cases, SMA is inherited in an autosomal recessive manner, meaning that the affected individual has two mutated genes, often inheriting one from each parent.
What age does SMA start? ›SMA type I is the most common and severe form of the condition. Signs and symptoms often begin within the first six months of life. Affected infants have severe muscle weakness and poor muscle tone which leads to significant developmental delay. Most are unable to support their heads or sit unassisted.
What are some facts about SMA? ›Spinal muscular atrophy (SMA) is a rare genetic disease and, if diagnosed early, can be treated quickly to stop the progression of the disease. SMA affects about 1 in every 11,000 babies born in the US. people in the United States (or 6.6 million* Americans) is a genetic carrier of SMA, and most don't know it.
Can you see SMA on ultrasound? ›Quantitative ultrasound has the potential of serving as a marker of SMA severity and may be useful in future clinical trials.
Is SMA screened at birth? ›Newborn screening for SMA can be included with routine newborn screening for other disorders during the first few days of life. Newborn screening for SMA looks for problems with the SMN1 gene. This process uses the same dried blood spots already collected for screening of other disorders.
Does SMA show up on MRI? ›Magnetic resonance imaging (MRI) can provide potential biomarkers for SMA. It has been used to assess muscle volume and fat fraction of the upper and lower extremities (Sproule et al., 2011; Durmus et al., 2017) and spinal cord atrophy (El Mendili et al., 2016; Querin et al., 2018).
What race is most affected by SMA? ›In the United States, the prevalence of SMA is estimated to be between 1 in every 6000 to 10,000 individuals. The condition is found in individuals of every race and ethnic background, but it is most common among Caucasians.
What is the death rate for SMA? ›In patients with SMA type I, the median survival is 7 months, with a mortality rate of 95% by age 18 months. Respiratory infections account for most deaths. In type II SMA, the age of death varies, but death is most often due to respiratory complications. See Prognosis for more information.
What is it like living with SMA? ›
People with SMA might not be able to walk or stand on their own, or they might lose their ability to do so later on in life. Children with type 2 SMA will have to use a wheelchair to get around. Children with type 3 SMA may be able to walk well into adulthood.
Does SMA hurt? ›Spinal muscular atrophy (SMA) causes a breakdown of motor neurons, which control muscle movement. Painful symptoms that occur with SMA include immobility and scoliosis. Secondary symptoms include gastrointestinal symptoms (reflux, etc.) and orthopedic symptoms (hip dislocation, osteoporosis, etc.).
What are the stages of muscle atrophy? ›There are three types of muscle atrophy: physiologic, pathologic, and neurogenic. Physiologic atrophy is caused by not using the muscles enough. This type of atrophy can often be reversed with exercise and better nutrition.
Which states test newborns for SMA? ›The 18 states with SMA screening programs in place are: Colorado, Connecticut, Indiana, Kansas, Kentucky, Maryland, Massachusetts, Minnesota, Missouri, Mississippi, New Hampshire, New York, Pennsylvania, Utah, Vermont, West Virginia, Wisconsin, and Wyoming.
Can SMA patients walk? ›Fifty percent of SMA patients who could walk without assistance and whose onset was prior to age 2 years lost the ability to walk independently by age 12. Fifty percent of SMA patients who walked and whose onset was between 2 and 6 years of age lost walking ability by age 44 years.
Can you walk with SMA Type 3? ›SMA Type 3 occurs in children who are at least 18 months old, with the first sign typically being leg weakness. Children with SMA 3 can sit, stand, and walk independently however the hallmark signs include difficulties with activities such as running, climbing stairs, or standing up from a seated position.
Can children with SMA talk? ›SMA1 prevents children from speaking a clearly understandable and fluent language, with their communication being mainly characterized by eye movements, guttural sounds, and anarthria (type 1a); severe dysarthria (type 1b); and nasal voice and dyslalia (type 1c).
How long do babies with SMA live? ›Infants with type 1 SMA usually die before their second birthday. Children with type 2 or type 3 SMA may live full lives depending on the severity of symptoms. People who develop SMA during adulthood (type 4) often remain active and enjoy a normal life expectancy.
Is SMA tested at birth? ›Newborn screening for SMA can be included with routine newborn screening for other disorders during the first few days of life. Newborn screening for SMA looks for problems with the SMN1 gene. This process uses the same dried blood spots already collected for screening of other disorders.
Does SMA qualify for disability? ›If your child has been diagnosed with Spinal Muscular Atrophy (SMA) Type 0 or 1, then you can feel confident that he or she will be eligible for Social Security disability benefits. Due to the Compassionate Allowances, you will be able to go through an expedited process when filing for the benefits.
Does SMA affect the eyes? ›
Adults with spinal muscular atrophy (SMA) usually do not experience weakness or impairment of any sort in the muscles controlling their eye movements, a recent study reported.
Can a child get SMA from one parent? ›An individual must inherit two non-functioning SMA genes – one from each parent – to have symptoms of SMA. If both parents are carriers there is a one in four (25 percent) chance that both will pass on the non-functioning gene, which would result in a pregnancy affected with spinal muscular atrophy.
Does SMA affect speech? ›Spinal muscular atrophy can affect the muscles of the tongue, jaw, and throat. This can impair patients' ability to chew, swallow, clear their throat, and speak. Speech therapy can help patients with SMA communicate more efficiently.
Who is the oldest person with SMA type 1? ›They have the hearts and minds and courage to keep learning.” Steve Mikita is one of the oldest people living with SMA at 64 years old.
Does SMA run in families? ›Yes. SMA is an inherited disorder that runs in families. If you have a family member who has SMA, it means that your risk of being a carrier is increased.
How many people in the US have SMA? ›Spinal Muscular Atrophy (SMA) is a genetic disorder that affects approximately 1 out of every 10,000 people.