14505 Spinal Muscular Atrophy Sma

Overview

Spinal muscular atrophy (SMA) is a genetic condition that causes muscle weakness and wasting. It affects the nerves in the spinal cord that control movement. The weakness can be mild or severe, depending on the type of SMA.

SMA is rare. It affects about 1 in 10,000 babies, and it is one of the most common genetic causes of death in children.

SMA can affect anyone, but it is usually diagnosed in infancy or early childhood. A milder form may appear in adolescence or adulthood. Both boys and girls are affected.

Symptoms

Common symptoms

• Progressive muscle weakness and wasting
• Trembling or shaking of the hands
• Difficulty with fine motor skills, such as writing or buttoning clothes
• Problems standing, walking, or climbing stairs
• Fatigue in muscles during activity

Symptoms in children

• Weak or floppy arms and legs (sometimes called floppy baby syndrome)
• Delayed milestones, such as not sitting up or crawling on time
• Difficulty holding the head up
• Tongue twitching or difficulty sucking and swallowing
• Breathing difficulties, especially during sleep

Symptoms in older adults

• Muscle weakness in the hands, arms, and legs first
• Difficulty walking or keeping balance
• Problems rising from a chair or climbing stairs
• Tremors in the fingers

Causes

Main causes

• A change (mutation) in the SMN1 gene, which is needed to make a protein for motor neurons
• The condition is usually inherited in an autosomal recessive pattern, meaning a child gets a faulty gene from each parent.

Risk factors

• A family history of SMA increases the chance of passing the gene on.
• Parents who are carriers of the faulty SMN1 gene have a one in four chance of having a child with SMA.

When to see a doctor

See a doctor urgently if:

• If you notice breathing difficulties, swallowing problems, or a sudden drop in muscle strength.
• If a baby becomes floppy, misses milestones, or has trouble feeding.

Book a routine appointment if:

• See a general practitioner if you or your child has muscle weakness, tremors, or trouble with movement that does not go away.
• Ask your GP about referral to a neurology or neuromuscular clinic.

Diagnosis

SMA is diagnosed with a blood test that looks for changes in the SMN1 gene. A doctor may also examine muscle tone, reflexes, and strength.

Tests that may be done

• Genetic blood test (first step and usually enough to confirm SMA)
• Electromyography (EMG) to check how nerves and muscles work
• Muscle biopsy (a small piece of muscle is taken and looked at under a microscope) in certain cases

What to expect at your appointment

You will meet a specialist team who will assess your child’s movement, breathing, swallowing, and feeding. The team may include a neurologist, physiotherapist, and genetic counsellor. Expect to have regular check-ups and tests to monitor progress.

Treatment

Treatment focuses on managing symptoms, supporting movement, and improving quality of life. Newer targeted therapies for SMA are now available and may slow or halt the disease, but these require specialist advice.

Self-care at home

• Use a wheelchair or walker if needed to stay active and independent.
• Do gentle stretching and moving to keep joints flexible.
• Support breathing with exercises or machines as recommended by your care team.
• Keep up with vaccines to reduce the risk of lung infections.

Medical treatments

Medical approaches for SMA include physical therapy, occupational therapy, breathing support (like non-invasive ventilation), nutritional support, and medicines that manage symptoms such as muscle spasms or excess saliva. Sometimes doctors recommend newer gene-based treatments, but they must be prescribed and supervised by a specialist centre.

When is surgery considered?

Surgery may be considered for children with severe scoliosis (curved spine) or to help with swallowing and feeding. Always discuss the risks and benefits with your care team.

Living with this condition

The daily experience of SMA depends on its severity. Many people need support with daily tasks such as dressing, bathing, and eating. A home care plan, adaptive equipment, and assistance from family or carers can make life easier.

Lifestyle tips

• Plan for rest breaks during activities.
• Use assistive devices like adapted keyboards, grasping aids, or a smartphone to help with everyday tasks.
• Travel and home modifications may help with accessibility.

Diet and exercise

A balanced diet keeps strength up and prevents weight gain, which can make movement harder. Talk with a dietitian if swallowing is difficult or you need help with feeding. Gentle exercise, guided by a physiotherapist, helps keep muscles as active as possible without overexertion.

Mental health and emotional wellbeing

Living with a progressive condition can be emotionally challenging. Anxiety, sadness, and frustration are common. Talk to a counsellor, join a support group, and remind yourself that needing help is okay. Children benefit from age-appropriate emotional support.

Prevention

SMA is a genetic condition, so it cannot be prevented. However, genetic counselling can help parents understand their chances of having another child with SMA. Prenatal tests can detect SMA during pregnancy.

Vaccines

Keeping immunisations, including the flu vaccine, up to date is important because respiratory infections can be dangerous for people with SMA.

Screening programmes

Newborn screening for SMA is available in some regions. If the test is offered, it can detect SMA early and allow prompt treatment. Couples planning a family can have carrier screening to learn if they are carriers.

Complications

If left untreated

• Breathing infections and respiratory failure
• Progressive loss of movement and mobility
• Severe scoliosis or joint contractures (joints fixed in a bent position)
• Difficulty swallowing, leading to poor nutrition or choking

Long-term outlook

There is no cure yet, but treatments are improving. Many children with SMA now have longer, healthier lives. With good support, many adults are employed, have families, and live independently. The outlook depends on the type and how early treatment starts, so staying in care with a specialist team is important.

Find support

External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.