

Spinal muscular atrophy (SMA) or spinal muscular dystrophy in children is a rare genetic condition that gradually affects muscle strength and movement. Parents always need to know the symptoms, possible treatment options, and the most important preventive steps to protect their child’s health and improve their quality of life. In this Dely Medical article, we will explore all the essential details about muscular atrophy in children, from early diagnosis to treatment options including medications, surgery, and exercises, as well as daily prevention tips and psychological support.
Spinal muscular atrophy (SMA) is a disease that affects the nerves and muscles in children. It causes muscles to weaken and shrink over time due to its impact on the motor neurons in the spinal cord.
SMA occurs due to a defect in the SMN1 gene. It is an autosomal recessive condition, meaning a child must inherit the faulty gene from both parents to develop the disease.
If both parents are carriers, there is a 1 in 4 chance that the child will have SMA with each pregnancy.
Testing can be done before birth if there is a family history of SMA.
In the U.S., newborns are now routinely screened for SMA for early detection.
Yes, especially the severe types, because SMA can affect respiratory muscles and increase the risk of lung infections.
Early treatment with medications and physical support can improve muscle strength and quality of life.
Children are more likely to develop SMA if:
One parent carries the faulty gene.
A sibling is already affected by the disease.
SMA has different types, and the age of onset and severity of symptoms varies:
Detected before birth.
May include joint or heart defects.
Respiratory problems at birth.
Many infants do not survive past 6 months.
Appears at birth or shortly after.
Difficulty lifting the head, sucking, swallowing, and feeding.
Very limited movement; chest muscles are weak.
Tongue movements may look like a worm-like motion.
Often leads to respiratory problems, with death usually before age 2.
Appears between 6 and 18 months.
General muscle weakness.
May need supportive devices like braces, walkers, or a wheelchair.
Many children can live into adolescence.
Appears between 2 and 17 years.
Difficulty walking and delayed motor development.
Mild muscle weakness; children usually live into adulthood.
Rare, usually appears in the 30s or 40s.
Causes gradual walking difficulties.
⚠️ Note: Some SMA symptoms can appear in other conditions, so always consult a pediatrician for proper diagnosis.
SMA can affect all ages, but early-onset cases are usually more severe. The disease is classified into four main types:
Symptoms appear from birth to 6 months.
Children cannot sit.
Severe respiratory problems; average life expectancy ~2 years.
Symptoms appear 7–8 months.
Children cannot stand without support.
Shorter life expectancy due to muscle and breathing weakness.
Symptoms appear after 18 months.
Less severe muscle weakness; children can move partially.
Longer life expectancy compared to Types 1 and 2.
Symptoms usually appear after age 18.
Patients may need a wheelchair around 50–60 years old.
⚠️ Note: Every case is unique; symptoms can vary, so regular follow-up with a specialist is essential.
Diagnosing SMA can be challenging, but doctors have accurate methods:
The doctor asks about the child’s symptoms, previous health, and family medical history.
A thorough physical exam is performed.
Used for early detection in newborns.
For older children, tests can measure muscle enzyme levels.
Genetic testing is now the most common method, especially if there is a family history.
A small muscle sample is taken and examined under a microscope.
Rarely performed now due to the availability of accurate genetic tests.
Measures the electrical activity of muscles.
Helps detect abnormal electrical signals caused by nerve or muscle problems.
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⚠️ Note: Early diagnosis is extremely important to provide the right treatment and support for the child, improving their quality of life.
The most common method for diagnosing SMA.
Detects defects or mutations in the SMN1 gene, which causes the disease.
Accuracy is around 95%, which is why some countries include it in routine newborn screening.
Measures muscle responses to signals sent by nerves.
Helps detect abnormal activity in muscles or nerves.
Creatine kinase (CK) test is important.
Elevated CK levels indicate muscle wasting and deterioration.
Muscle Biopsy:
A small sample of muscle is taken and examined under a microscope.
Rarely used now due to the availability of precise genetic tests.
Amniocentesis:
Prenatal test, usually done around week 14 of pregnancy.
A sample of amniotic fluid is taken to check for SMA.
Chorionic Villus Sampling (CVS):
A small sample of the placenta is taken during pregnancy to assess the likelihood of SMA in the fetus.
⚠️ Note: The choice of test depends on the child’s age, symptoms, and family history. Early diagnosis allows for prompt treatment and support.
Here’s a comparison between normal child development and development in children with SMA:
Age | Normal Development ???? | Development in SMA Children ???? |
---|---|---|
Birth – 3 months | Lifts head while lying on tummy, follows with eyes, makes simple sounds | Weak limb movements, difficulty lifting or holding the head |
3 – 6 months | Rolls over, grasps toys, laughs aloud | Difficulty or inability to roll, weak grasp, general muscle floppiness |
6 – 9 months | Sits without support, transfers toys hand-to-hand, starts babbling (“ba”, “ma”) | Cannot sit alone, needs full support, very limited movements |
9 – 12 months | Crawls, points, says first simple words | Usually cannot crawl, prefers lying on back, difficulty speaking or expressing self |
1 – 2 years | Takes first steps, uses 2–3 words, explores surroundings | Cannot walk, relies on wheelchair or assistance, mental development is normal but movement is very limited |
2 – 5 years | Runs, climbs stairs, forms simple sentences, plays with others | Needs a wheelchair, may have swallowing or breathing difficulties, but communication and understanding are normal |
Over 5 years | Participates in daily activities, develops social and learning skills | Heavily relies on assistive devices (wheelchair, respiratory aids, physiotherapy), cognitive skills are like any normal child |
Cognitive development in children with SMA is usually normal; the main challenge is muscle strength and mobility.
Early treatment with modern medications such as Nusinersen (Spinraza) or Zolgensma, combined with physical therapy, significantly improves motor development and mobility.
Children with SMA have special nutritional needs due to muscle weakness and difficulty swallowing and chewing, which are essential to maintain health and weight.
Difficulty swallowing and chewing because of weak muscles.
The body needs enough calories and protein to maintain muscles and reduce wasting.
Easily digestible protein: yogurt, cottage cheese, boiled eggs, lentil or chicken soup.
Calorie-rich foods: potatoes, avocado, whole grains like oats or brown rice.
Healthy fats: olive oil, coconut oil, ground nuts (if the child can swallow safely).
Soft fruits and vegetables: cooked carrots, zucchini, mashed apple, banana.
Mash or grind food to make swallowing easier.
Divide meals into small, frequent portions throughout the day.
Use a suitable consistency: not too runny, not too thick.
Vitamin D and calcium to strengthen bones.
Omega-3 to support the brain and nervous system.
Medical protein powder if the child needs extra calories.
Some children may need a feeding tube (G-tube) if swallowing is unsafe.
Monitor weight and height regularly to ensure proper nutrition.
Treatment can be gene-targeted therapy to address the cause or supportive medications to manage symptoms, depending on the child’s condition and access to therapy.
These are modern drugs that target the genetic cause of SMA, helping the body produce SMN protein, which is essential for nerve and muscle health:
Nusinersen (Spinraza)
Administered via injection into the spinal canal.
Increases SMN protein production and slows muscle loss.
Requires regular doses according to the doctor’s protocol.
Onasemnogene abeparvovec (Zolgensma)
Gene therapy given once intravenously.
Delivers a healthy copy of the SMN gene to children under ~2 years.
Most effective if started early in the disease.
Risdiplam (Evrysdi)
Oral daily medication.
Increases SMN protein production throughout the body.
Suitable for older children or those unable to receive injections.
Not all children can access gene therapy, and some need additional support:
Muscle-strengthening medications: can improve muscle strength in some cases.
Respiratory support medications: for children with breathing difficulties.
Protein, Vitamin D, Calcium: Support muscle strength and bone health.
⚠️ Note: Early treatment is crucial to improve mobility and reduce complications. Early diagnosis and regular follow-up with a specialist are essential.
Children with SMA may sometimes require surgery to improve mobility, breathing, or nutrition, depending on their condition.
Children with SMA often develop spinal curvature due to weak muscles.
Surgery may involve metal rods to correct the spine.
Goal: Improve sitting posture, breathing, and reduce pain.
Some children experience weak chest muscles and breathing difficulties.
In rare cases, a tracheostomy may be required for long-term respiratory support.
Some children have difficulty swallowing or feeding.
A G-tube (feeding tube) may be inserted to deliver food directly to the stomach.
Goal: Ensure proper nutrition and prevent weight loss or malnutrition.
⚠️ Note: Surgical interventions are performed after a full evaluation by a specialist and aim to safely improve the child’s quality of life.
Exercise is very important for children with SMA as it helps strengthen muscles, improve mobility, and support breathing.
Strengthens weak muscles and improves mobility.
Exercises for sitting, crawling, and walking according to the child’s ability.
Prevents joint stiffness and muscle contractures.
Improves balance and daily movement.
Teaches children to perform daily activities: holding objects, playing, and using simple tools.
Enhances hand-eye coordination.
Supports independence as much as possible.
For children with weak chest muscles.
Improves breathing strength and prevents lung complications.
Includes deep inhalation and exhalation exercises, or use of breathing support devices.
Supports muscles without putting too much pressure on joints.
Improves movement and physical fitness.
Gentle movement of limbs to prevent joint stiffness.
⚠️ Note: Exercises must be adapted to the child’s ability and supervised by a physiotherapist or occupational therapist to avoid injuries and achieve the best results.
Day | Age 0–2 yrs (Light–Moderate) | Age 3–6 yrs (Moderate–Light) | Age 7–12 yrs (Light–Moderate) |
---|---|---|---|
Saturday | Neck & shoulder: lift head while lying on tummy 3×10 sec. Limbs: bend and extend arms & legs gently 5–10 reps. |
Balance: sit on soft ball with assistance 5 min. Hand-eye: hold and pass a light ball. |
Strength: lift legs while lying on back 3×10. Balance: stand with support, try simple squats. |
Sunday | Breathing: deep inhale & exhale 5 times. Core: lift head while lying on tummy. |
Crawling/Walking: assist child to crawl/walk 5–10 min. | Strength & endurance: light resistance bands for arms & hands. Balance: stand on one leg with assistance. |
Monday | Limbs: move arms & legs gently to prevent stiffness, 10 reps each. | Sitting: sit on floor with support, reach for toys. | Breathing: inhale/exhale with 3-sec hold ×5. Hand-eye: small ball passing between hands. |
Tuesday | Virtual swimming: move limbs in water (or on floor if no pool) 5 min. | Strength: gently press a soft ball between hands 5×3 sets. | General movement: walk with support or short distances on floor. |
Wednesday | Neck & back: lift head and chest while lying on tummy 3×10 sec. | Balance: sit on ball with assistance, bend forward & backward. | Strength: lift light weights or use resistance bands for arms & legs. |
Thursday | Breathing: deep inhale & exhale, use breathing device if needed. Hands: open & close gently 10 times. |
Crawling/Walking: assist child to crawl or walk 5–10 min. | Balance: stand on one leg with support, or walk on a straight line. |
Friday | Active rest: gentle massage & stretching to prevent stiffness. | Active rest: light exercise for limbs & neck. | Active rest: relaxation & stretching for muscles & joints. |
Repeat each exercise according to the child’s ability; stop immediately if the child feels pain or fatigue.
Adjust the duration of exercises based on the child’s daily condition.
Adding aquatic therapy (swimming) can improve muscle strength and reduce joint pressure.
Regular short sessions are better than one long session.
Monitor progress regularly with a physiotherapist to ensure safety and optimal results.
SMA is a genetic disorder, so it cannot be completely prevented after birth. However, steps can be taken to reduce damage and improve quality of life:
Early diagnosis in high-risk children allows prompt medical intervention.
Includes genetic testing and muscle assessments if any signs of weakness or delayed development appear.
Disease-targeted medications help improve muscle strength and slow disease progression, such as:
Nusinersen (Spinraza)
Risdiplam (Evrysdi)
Onasemnogene abeparvovec (Zolgensma)
Daily exercise programs to strengthen muscles and maintain flexibility.
Support the child in sitting, crawling, walking, or using assistive devices when needed.
Monitor the child’s weight and diet to reduce complications from muscle weakness.
Provide soft and easily digestible foods if the child has difficulty swallowing.
Teach the child how to perform daily activities safely.
Support parents in managing the challenges of the disease and providing a suitable environment for the child.
⚠️ Note: Early detection, timely medication, daily exercises, proper nutrition, and psychological support are all key factors in improving the quality of life for children with SMA.