SMA (Spinal Muscular Atrophy) Disease: What is it, Causes, Symptoms and Treatment
SMA is a neurological disease that affects motor neurons.
SMA is a neurological disease that affects motor neurons. This disease, which causes muscle weakness and wasting, can have life-threatening consequences when it begins to affect the respiratory muscles. Although a definitive solution to the disease is not possible, the progression of the disease can be stopped with appropriate treatment.
What is SMA?
Spinal muscular atrophy (SMA) is the name given to a group of genetic diseases that cause muscle shrinkage. SMA occurs after loss of nerve cells in the brain stem and spinal cord. As a result of this situation, there is a loss of function in the muscles innervated by the relevant nerves and these muscles atrophy. SMA patient due to muscles atrophying or, to put it more clearly, wasting; He or she may have problems performing movements such as walking, standing up, controlling head movements, swallowing, and breathing.
While some types of SMA are present in patients from birth, some types of SMA begin to show effects later in life. It is known that SMA disease is seen in approximately one in every 8,000-10,000 people.
SMA is a disease that gradually progresses and causes more serious symptoms. Today, there is no treatment that completely cures SMA disease. However, thanks to developed treatments, it may be possible to slow or stop the progression of the disease. Again, with these treatments, the symptoms seen in the patient can be alleviated and the patient’s quality of life can be increased.
What are the Types of SMA?
There are different types of SMA. When dividing SMA into types, various parameters such as the age at which symptoms begin to appear in the patient, the patient’s life expectancy and quality of life are taken into consideration. SMA types:
- SMA Type 1: This type of SMA, also known as Werdnig-Hoffmann disease, begins to show its effects in the first 6 months of life. If the disease is not treated early, the baby may die before the age of 1. In SMA Type 1, it may cause symptoms such as muscle twitching, limitation in limb movements, and difficulty in feeding. These patients often do not have the skills to sit, stand, or walk. However, with new treatment methods, these babies can be given the ability to sit and walk.
SMA Type 1 can be diagnosed by the decrease in the movements of the baby in the womb in the last months of pregnancy. Movement difficulties in the baby become more evident within a few months after birth.
- SMA Type 2: This type of SMA usually occurs when the baby is 6-18 months old. The baby can learn to sit before the disease takes effect. However, after the disease occurs, it is not possible for the baby to stand and walk. Patients who do not receive treatment may also lose their ability to sit. Life expectancy in type 2 SMA patients varies depending on whether the patient has respiratory distress. Most SMA type 2 patients can survive into young adulthood.
- SMA Type 3: Also known as Kugelberg-Welander disease, this disease occurs after the 18th month of life. In SMA type 3 patients, problems that restrict joint movement may occur, such as scoliosis and contracture due to shortening of the muscle or tendon. Type 3 patients largely preserve their skills such as sitting and walking. However, they have difficulty performing movements such as running, jumping, and climbing. These patients may experience tremors in their fingers. Again, these patients are at risk for severe respiratory infections. If SMA Type 3 patients receive appropriate treatment, life expectancy becomes close to the average life expectancy of a healthy person.
- SMA Type 4: This disease, also known as Adult Type SMA, occurs after the age of 21. In these patients, there is weakness in the proximal muscles close to the trunk, but this weakness is mild.
What are the Symptoms of SMA?
The symptoms seen in SMA disease vary depending on the type of disease and the time it occurs.
Symptoms seen in SMA Type 1:
- Weakness and limpness (hypotonia) in the arms and legs
- Weak, powerless crying
- Difficulty moving, swallowing and breathing
- It can be listed as difficulty in holding the head or sitting without support.
Symptoms occurring in SMA Type 2 tend to be milder than those in Type 1. Symptoms seen in this type:
- Difficulty standing up on your own
- Weakness in arms and legs
- Tremors in hands and fingers
- Scoliosis (S or C-shaped curvature of the spine)
- Weakening of respiratory muscles
- It can be considered as difficulty in coughing.
SMA Type 3 patients can stand up and walk on their own. However, patients may lose these abilities over time. Additional symptoms seen in patients:
- Having difficulty standing up from a sitting position
- balance problems
- Difficulty climbing stairs and running
- It can be listed as scoliosis.
Symptoms seen in SMA Type 4:
- Weakness in hands and feet
- difficulty walking
- It is in the form of tremors and twitching in the muscles.
What Causes SMA?
SMA occurs as a result of changes in genes called SMN1 and SMN2. Changes in these genes cause motor neurons in the spinal cord and brainstem to fail to function.
Motor neurons are nerve cells that control movements. The SMN1 and SMN2 genes are responsible for the production of a protein that is necessary for motor neurons to function.
While the SMN1 gene leads to the formation of SMA, the SMN2 gene determines the severity and course of the disease.
One in 40 to 60 people in the population has a genetic change that leads to SMA formation. However, in order for a person to have SMA, he must inherit changed genes from both his mother and father. However, even if a person inherits these genes from both parents, there is a 25% chance of getting the disease. As a result, people can live healthy lives even if they have genetically modified genes.
How to Diagnose SMA?
Diagnosis of SMA usually begins when families notice the symptoms of SMA in their child. The doctor questions the child’s symptoms in detail and takes the medical history of the child and the family. Physical examination of the child is very important for diagnosis. If conditions such as weakness or laxity in the child’s muscles are detected, further examinations are required.
Methods such as blood test, muscle biopsy and electromyography (EMG) can be used to diagnose SMA. With EMG, the muscle and the neurons responsible for nerve transmission of the muscle are evaluated.
If SMA is suspected during pregnancy, diagnosis can be made by amniocentesis and chorionic villus sampling.
What are the symptoms that occur with SMA?
SMA patients may be prone to respiratory system infections. It can cause serious problems, especially in patients with pneumonia that affects the lower respiratory tract. It causes symptoms such as cough, fever, shortness of breath, wheezing, nausea and vomiting in patients with pneumonia.
Is There a Treatment for SMA?
SMA is a disease that cannot be completely treated. However, it may be possible to stop the progression of the disease with some treatment methods developed today. SMA is a disorder with increasingly severe characteristics. With treatment, this aggravation is stopped and the patient’s sitting and walking gains are maintained.
There are drugs targeting newly developed gene therapy for the treatment of the disease. In addition to drug treatment, practices that enable the SMA patient to actively participate in life also improve the patient’s quality of life. It is beneficial for the patient to do breathing exercises, regulate his nutrition, and do activities that help stretch and stretch his muscles. Assistive devices such as ventilators and battery-powered wheelchairs also help improve the patient’s quality of life.
The patient and the patient’s relatives should be informed about SMA disease, and the patient’s close circle should be supportive about SMA; These are behaviors that increase treatment compliance. It would be beneficial for SMA patients to apply to a well-equipped health center for both medication and supportive treatments.