What Is the Life Expectancy of Someone with Spinal Muscular Atrophy?

Spinal muscular atrophy affects the nerves that control muscular strength and movement. These nerves are found in the spinal cord and lower section of the brain (known as motor neurons). When SMA strikes, the nerves are unable to transmit impulses from the brain to muscles. In the absence of nerve signals, the muscle cells shrivel and ultimately degenerate.

A mutation in the SMN1 gene is responsible for the majority of instances of spinal muscular atrophy (SMA). A protein necessary for proper motor neuron activity is not produced in sufficient amounts by this gene. Motor neurons perish and are, thus, unable to transmit muscular impulses.

A child with SMA receives one copy of the SMN1 gene from each parent. A child who inherits the SMN1 gene from only one parent is unlikely to develop SMA although they may pass it on to their children.

Based on the severity of the disease and the age at which symptoms first show, spinal muscular atrophy (SMA) is categorized into four groups.

1. Type I: Also known as Werdnig–Hoffmann disease or infantile-onset SMA, this is the most common and severe type. It affects infants from birth to six months of age, with the majority of babies showing symptoms by three months.
2. Type II: Affects children who are between 7 and 18 months of age. Children can sit but not walk on their own. This type can range in severity from modest to severe.
3. Type III: Commonly known as Kugelberg–Welander syndrome or juvenile SMA, this affects children from 18 months of age to adolescence. Although children can walk on their own, their arms and legs are weak, and they are prone to falling. This is the mildest form of SMA in youngsters.
4. Type IV: The adult type of SMA with symptoms commonly appearing after 35 years of age and gradually worsening over time.

Spinal muscular atrophy (SMA) can show up in various ways. Some newborns with SMA are “floppy,” meaning they don't learn to roll or sit when they should. An older child may fall more frequently or have more difficulties lifting objects than a younger child.

If the back muscles are weak, scoliosis (a curved spine) can occur in children with SMA. A child with severe SMA may be unable to stand or walk, and eating and breathing may require assistance.

Spinal muscular atrophy (SMA) is diagnosed in various ways.

Doctors may conduct the following tests if they suspect a kid has SMA:

• Genetic testing: The most prevalent method of detecting SMA is where the SMN1 gene is tested for a deletion or variant.
• Biopsy: Doctors take a small sample of the muscle to examine it under a microscope.

Although there is no cure for spinal muscular atrophy (SMA), the following treatments can help children with the condition:

• Nusinersen (also known as SpinrazaTM):
  • A novel SMA treatment was authorized in 2016.
  • This medication increases the quantity of protein produced by the SMN1 gene that is deficient in the body.
  • It works by the production of the SMN2 gene that acts as a backup, looks more like the SMN1 gene, and creates the required protein.
  • A spinal tap is used to administer this medicine.
  • Four doses are given over two months, followed by four doses every four months after that.
  • According to studies, breathing, motor function, and survival all improved significantly after administering this medication.
• Trials of gene therapy:
  • These are ongoing and have proved to improve overall function in patients with SMA.
• Supportive treatments:
  • A mask/mouthpiece or breathing machine can help with breathing. Tracheostomy may be required (a tube is surgically inserted into the trachea to help in breathing)
  • Treatments to help children clear mucus that can aid in the prevention of illnesses and adequate nutrition. Feeding tubes may be used
  • Scoliosis can be managed with medication, splint, brace, or surgery
  • Physical and occupational therapy
  • Support groups and counseling