Is your child's muscles getting weak? This could be Spinal Muscular Atrophy (SMA)

Have you noticed that your little one is struggling and moving his limbs less than other children? Is it difficult for him to hold his neck straight? Or does your older child seem to be having difficulty walking, running, or jumping, and is his body becoming increasingly weak? It is very normal for you, as a mother or father, to feel fear and anxiety when you see these things. Today we are talking about a disease that can cause such symptoms, but is not talked about much in our country, but it is very important to be aware of. That is Spinal Muscular Atrophy , which we doctors call (SMA) for short.

Simply put, what is this SMA?

Spinal Muscular Atrophy (SMA) is a genetic (inherited) disease . That is, it is something that is passed down from parents to children. This disease affects our body's nervous system, causing our muscles to gradually weaken and waste away. We call this (atrophy) in medical science.

Let's understand this a little more simply. Imagine that the muscles in our body are like light bulbs. In order for these bulbs to light up, electricity needs to come from the switch through a wire. In the same way, messages from our brain (like electricity) need to go to the muscles (the bulbs) through a special type of nerve cell (these are like the wire) in the spinal cord. We call these special nerve cells lower motor neurons .

In SMA, the nerve cells (motor neurons) in the spinal cord gradually die. Then, messages from the brain don't reach the muscles. The result? The muscles don't receive the messages to work, so they gradually weaken and shrink.

What are the main types of SMA?

SMA is not all the same. Doctors divide it into 5 main types based on the age at which symptoms begin, the severity of the disease, and life expectancy. Understanding this classification can help you gain a better understanding of the disease.

Why does this SMA disease occur?

This is a completely genetic disease, meaning it is not caused by an environmental factor or infection.

A special type of protein is essential to keep the motor neurons in our body healthy. The main gene that instructs the production of this protein is the `SMN1` (survivor motor neuron 1) gene . A child with SMA has a defect in this `SMN1` gene. Therefore, the necessary protein is not produced in the body.

But, fortunately, we have another 'helper' gene in our body that makes a little bit of this protein, the `SMN2` gene . But it only makes a very small amount of it. The severity of the disease varies depending on the number of copies of the `SMN2` gene a person has. If the number of `SMN2` copies is higher, the symptoms may be less severe. That is why some people have a severe condition like Type 1, while others have a mild condition like Type 4.

How is this disease inherited?

SMA is inherited in an autosomal recessive pattern. This may sound like a complicated term, but it simply goes like this:

• For a child to develop SMA, the child must inherit the defective `SMN1` gene from both the mother and the father.
• In most cases, both parents are just 'carriers' of this faulty gene. This means they don't have symptoms, but they have one copy of this faulty gene in their body.
• Every time two carrier parents have a child, there is a 25% chance that the child will have SMA.

How is SMA diagnosed?

If you think your child may have symptoms of SMA, the first thing you should do is see a qualified doctor. The doctor will ask you about your child's symptoms and examine your child carefully.

The main and most accurate way to confirm SMA is through genetic testing.

• Genetic testing: This is a simple blood test that can accurately identify 95% of SMA patients by identifying the defect in the `SMN1` gene.
• Other tests: Sometimes, if the symptoms are similar to other neurological diseases, the doctor may recommend some other tests.
• Creatine kinase (CK) blood test: This enzyme is elevated in other diseases that damage muscle. However, in SMA, it is usually normal.
• Electromyogram (EMG): A test that measures the electrical activity of muscles and nerves.
• Muscle biopsy: Very rarely, a small piece of muscle is taken for examination.

Can this be detected during pregnancy?

Yes. If there is a history of SMA in your family or if you and your partner are known to be carriers, you can test your fetus for the disease during pregnancy.

• Amniocentesis: After 14 weeks of pregnancy, a very fine needle is passed through the mother's abdomen to remove a small sample of the amniotic fluid surrounding the fetus.
• Chorionic villus sampling (CVS): A procedure that involves taking a small piece of tissue from the placenta as early as 10 weeks of pregnancy.

You can learn more about these tests by talking to your doctor.

What are the treatments for SMA?

Unfortunately, there is no cure for SMA yet. But don't lose hope. Things are much different today than they were 10 years ago. There are many things you can do to control symptoms, improve your child's quality of life, and prevent complications. In addition, new, highly effective treatments have recently become available that can change the course of the disease.

1. Symptom management and support services

These make daily life easier for the child and help them stay strong.

• Physical therapy: Helps strengthen muscles, prevent joint stiffness , and maintain correct posture.
• Occupational therapy: Helps the child perform daily tasks independently, such as eating and dressing.
• Assistive devices: Things like walkers, wheelchairs, and braces to keep your back straight.
• Speech and swallowing therapy: Helps children with swallowing difficulties learn to eat safely.
• Feeding: If swallowing is very difficult, a feeding tube is inserted through the nose or through the abdomen directly into the stomach.
• Respiratory support: Special machines (assisted ventilation) are used for breathing difficulties.

2. Modern pharmacological treatments

These are the things that have revolutionized SMA treatment. They address the underlying cause of the disease, protein deficiency.

• Disease-modifying therapy: These drugs stimulate a helper gene called `SMN2`, causing it to produce more SMN protein.
• Nusinersen (Spinraza®): This is a medication that is injected into the fluid around the spinal cord.
• Risdiplam (Evrysdi®): This is a daily oral medication.
• Gene replacement therapy:
• Onasemnogene abeparvovec-xioi (Zolgensma®): This is one of the most expensive drugs in the world. It works by replacing the defective SMN1 gene with a healthy, functional SMN1 gene. It is a one-time intravenous (IV) infusion for children under 2 years of age.

Questions to ask your doctor

It's normal to have a lot of questions in your mind when you find out that your child has SMA. Don't hold anything back, ask your doctor.

• What type of SMA does my child have?
• What kind of situation can we expect in the future according to this type?
• What treatments are best for my child?
• Are there any side effects to these treatments?
• Are other members of our family or our next child at risk of developing this disease? Should we get genetic testing?
• What ongoing care does the child need?
• What symptoms of complications should I be especially aware of?

Dealing with an SMA diagnosis can be challenging. But remember, you are not alone. With the right medical advice, treatment, and the love and support of family, you can give your child the best life possible.