Table of ContentsView AllTable of ContentsTypesSymptomsCausesDiagnosisTreatmentCaregiving for a ChildOutlookSupport
Table of ContentsView All
View All
Table of Contents
Types
Symptoms
Causes
Diagnosis
Treatment
Caregiving for a Child
Outlook
Support
This article will discuss spinal muscular atrophy, its different types, symptoms, causes, diagnosis, treatment, and caring for a child with the condition. New treatments are offering hope of altering the progress of SMA.
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Spinal Muscular Atrophy (SMA) Types
Several types have other names that can be used to define them, including:
Symptoms of SMA
The symptoms and effects of SMA are all related to muscle weakness. However, the severity of the effects varies based on the SMA type that a person has.
Children who have type 0 SMA or type 1 SMA do not develop physical strength, while people who have type 2 SMA, type 3 SMA, and type 4 SMA will experience a decline in their abilities after beginning to develop motor strength and control.
In addition to muscle weakness, people with all types of SMA will experiencemuscle atrophy,which isdegeneration and thinning of the muscles.
Symptoms of SMA can include:
People with mild forms of SMA who can breathe on their own may have difficulty breathing when they become sick or develop an infection. During these times, a person with SMA may need respiratory support, even if they do not regularly need respiratory support.
What Causes SMA?
Without an adequate amount of SMN protein, the neurons degenerate, and SMA progresses over time.It can progress very rapidly for people who have a very low amount of the SMN protein.
There is another gene, SMN2, that also codes for the SMN protein. People have several copies of the SMN2 gene, but the number varies. With more copies of SMN2, a person who has SMA will have a milder form of the disease,with a later age of onset, less nerve damage, less disability, and a longer life expectancy.
Hereditary Pattern of SMA
The genetic mutation that causes SMA is almost always expressed in a recessive pattern.This means that a person would develop clinical effects of SMA only if both of their SMN1 genes are altered and cannot produce SMN protein. As the gene is not on a sex chromosome, the risks are the same for people of any sex.
A child with parents who do not have any signs of SMA can develop the condition if their parents each carry one copy of SMN1 gene with the mutationandthe child inherits a copy of the altered gene from each parent.
How Is SMA Diagnosed?
The diagnosis of SMA is confirmed withgenetic testing. For people who have a family history of this condition, genetic testing may confirm or rule out the diagnosis even before any symptoms occur.
When a person doesn’t have a family history of SMA, the diagnostic process involves an evaluation of symptoms and a physical exam before tests are ordered. Depending on the symptoms and initial medical evaluation, tests that might be ordered could include blood tests,electromyography(EMG),nerve conduction studies(NCV),muscle biopsy, and spine or brain imaging tests.
Screening for SMASome states have programs for neonatal screening for SMA.If you think your child could be at risk, or if you are wondering whether they have been screened or tested at any stage in their life, you can check with your child’s pediatrician.
Screening for SMA
Some states have programs for neonatal screening for SMA.If you think your child could be at risk, or if you are wondering whether they have been screened or tested at any stage in their life, you can check with your child’s pediatrician.
Types of Motor Neuron Diseases
Medical Observation and Surveillance After Diagnosis
After a definitive diagnosis, ongoing evaluation of neuromuscular function is necessary. It is important for children and adults who have SMA to get regular physical examinations so that changes in muscle function and posture can be detected, even before symptoms become obvious.
This medical surveillance can help with treatment planning and with knowing when to begin to use supportive devices and mobility devices. Families can also benefit from anticipating the type of assistance their loved one is expected to need and whether it’s best to look for professional caregivers.
Spinal Muscular Atrophy Treatment
Treatment for SMA has been substantially changed within the past decade. New disease-modifying treatments can impact the disease process. Additionally, therapies and interventions that help alleviate complications are also a necessary part of treatment.
Disease-modifying therapies for SMA include:
These therapies are more effective when they’re started at early stages of the disease before substantial disability has developed.However, the effects can be variable,and the protocols for starting treatment or for combining therapies are modified as changes and familiarity with the medical treatments increase.
Physical therapy can help a person with SMA slow muscle weakness and atrophy through stretching and strengthening exercises.Occupational therapy can help the person perform everyday tasks of self-care and recommend assistive devices and home modifications.
Caring for a Child with Spinal Muscular Atrophy
If you have SMA, you might need assistance with grooming, bathing, or using the toilet. You might need to consider accessibility when using public spaces, such as calling ahead to ask if the place where you want to go has ramps or wide hallways.
Devices used for care may include:
Some interventions are external, such as braces, but some are more invasive and require surgery or a minimally invasive procedure. A person with SMA should try to be as active as possible to help maintain muscle function.
Verywell / Lara Antal
SMA Outlook
The outlook and life expectancy for SMA varies, depending on the type of SMA that a person has.
When medical therapy and intervention begin at an early stage of the disease, the outlook can substantially improve for those who have a milder type of SMA. People with types 3 or 4 SMA may have a normal life expectancy. Those with type 2 have a variable outlook, but most live into their 20s or 30s.
Life expectancy with SMA can be as short as a few days with type 0 SMA and just a few months or up to a year with type 1 SMA.
SMA Support
Awareness of SMA has been increasing. A number of different groups are available to help you navigate life as a person with SMA or a caregiver of a loved one with SMA.
If you have a child who is at risk or who has been diagnosed with SMA, you might benefit from joining a group so that you can receive and provide emotional support and practical advice about what to expect and how to manage.
If you are living with SMA, you might benefit from being part of a community of people who have experienced and continue to experience the same challenges and triumphs that you are going through.
Groups you might consider reaching out to includeCure SMA,Muscular Dystrophy Association, andSMA Foundation.
Summary
Many people who develop SMA do not have a family member with the condition, and the diagnosis in those cases may occur after symptoms begin. There are medical disease modifying treatments that can help alleviate the severity of SMA, and supportive care is an important part of managing life with SMA.
Support groups and services can help you with advice, resources, access to services, and with staying up-to-date on the most recent developments in SMA therapy.
8 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Mercuri E, Sumner CJ, Muntoni F, Darras BT, Finkel RS.Spinal muscular atrophy.Nat Rev Dis Primers.2022;8(1):52. doi:10.1038/s41572-022-00380-8National Institute of Neurological Disorders and Stroke.Nusinersen (Spinraza) — spinal muscular atrophy (SMA).National Institute of Neurological Disorders and Stroke.Spinal muscular atrophy.Centers for Disease Control and Prevention.Spinal muscular atrophy (SMA).Stępień A, Jędrzejowska M, Guzek K, Rekowski W, Stępowska J.Reliability of four tests to assess body posture and the range of selected movements in individuals with spinal muscular atrophy.BMC Musculoskelet Disord. 2019;20(1):54. doi:10.1186/s12891-018-2389-8Nance JR.Spinal muscular atrophy.Continuum (Minneap Minn).2020;26(5):1348-1368. doi:10.1212/CON.0000000000000918Reilly A, Chehade L, Kothary R.Curing SMA: Are we there yet?Gene Ther.2023;30(1-2):8-17. doi:10.1038/s41434-022-00349-yMedlinePlus.Spinal muscular atrophy.
8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Mercuri E, Sumner CJ, Muntoni F, Darras BT, Finkel RS.Spinal muscular atrophy.Nat Rev Dis Primers.2022;8(1):52. doi:10.1038/s41572-022-00380-8National Institute of Neurological Disorders and Stroke.Nusinersen (Spinraza) — spinal muscular atrophy (SMA).National Institute of Neurological Disorders and Stroke.Spinal muscular atrophy.Centers for Disease Control and Prevention.Spinal muscular atrophy (SMA).Stępień A, Jędrzejowska M, Guzek K, Rekowski W, Stępowska J.Reliability of four tests to assess body posture and the range of selected movements in individuals with spinal muscular atrophy.BMC Musculoskelet Disord. 2019;20(1):54. doi:10.1186/s12891-018-2389-8Nance JR.Spinal muscular atrophy.Continuum (Minneap Minn).2020;26(5):1348-1368. doi:10.1212/CON.0000000000000918Reilly A, Chehade L, Kothary R.Curing SMA: Are we there yet?Gene Ther.2023;30(1-2):8-17. doi:10.1038/s41434-022-00349-yMedlinePlus.Spinal muscular atrophy.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Mercuri E, Sumner CJ, Muntoni F, Darras BT, Finkel RS.Spinal muscular atrophy.Nat Rev Dis Primers.2022;8(1):52. doi:10.1038/s41572-022-00380-8National Institute of Neurological Disorders and Stroke.Nusinersen (Spinraza) — spinal muscular atrophy (SMA).National Institute of Neurological Disorders and Stroke.Spinal muscular atrophy.Centers for Disease Control and Prevention.Spinal muscular atrophy (SMA).Stępień A, Jędrzejowska M, Guzek K, Rekowski W, Stępowska J.Reliability of four tests to assess body posture and the range of selected movements in individuals with spinal muscular atrophy.BMC Musculoskelet Disord. 2019;20(1):54. doi:10.1186/s12891-018-2389-8Nance JR.Spinal muscular atrophy.Continuum (Minneap Minn).2020;26(5):1348-1368. doi:10.1212/CON.0000000000000918Reilly A, Chehade L, Kothary R.Curing SMA: Are we there yet?Gene Ther.2023;30(1-2):8-17. doi:10.1038/s41434-022-00349-yMedlinePlus.Spinal muscular atrophy.
Mercuri E, Sumner CJ, Muntoni F, Darras BT, Finkel RS.Spinal muscular atrophy.Nat Rev Dis Primers.2022;8(1):52. doi:10.1038/s41572-022-00380-8
National Institute of Neurological Disorders and Stroke.Nusinersen (Spinraza) — spinal muscular atrophy (SMA).
National Institute of Neurological Disorders and Stroke.Spinal muscular atrophy.
Centers for Disease Control and Prevention.Spinal muscular atrophy (SMA).
Stępień A, Jędrzejowska M, Guzek K, Rekowski W, Stępowska J.Reliability of four tests to assess body posture and the range of selected movements in individuals with spinal muscular atrophy.BMC Musculoskelet Disord. 2019;20(1):54. doi:10.1186/s12891-018-2389-8
Nance JR.Spinal muscular atrophy.Continuum (Minneap Minn).2020;26(5):1348-1368. doi:10.1212/CON.0000000000000918
Reilly A, Chehade L, Kothary R.Curing SMA: Are we there yet?Gene Ther.2023;30(1-2):8-17. doi:10.1038/s41434-022-00349-y
MedlinePlus.Spinal muscular atrophy.
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