Spinal Muscular Atrophy (SMA disease)


What is SMA disease?

Spinal muscular atrophy (SMA) is a rare inherited condition that affects motor nerve cells in the spinal cord and in the lower part of the brain.

There are four types of SMA

Spinal Muscular Atrophy Type 1

Type 1 is the most severe form.

It is also known as Werdnig-Hoffmann disease and it is often present at birth and symptoms begin within a months after birth.

Children can’t sit without support and have also trouble feeding and breathing

Spinal Muscular Atrophy Type 1 life expectancy is within 2 years after birth.

SMA is the first genetic cause of infant mortality.

Spinal Muscular Atrophy Type 2

This is an intermediate form. Children can sit without support but can’t get a sitting position by themselves and can not walk.

Symptoms show between 6 and 18 months of age.

Spinal Muscular Atrophy Type 3

This is the milder form and it also called Kugelberg-Welander disease.

It affects children after 18 months and it can occurs also during adolescence.

Children are usually able to walk, but some may need a wheelchair.

SMA Type 4

There is a fourth type of SMA that can affect adults, usually symptoms appear after 35 years old and have a slow progression.


Spinal muscular atrophy symptoms

SMA disease symptoms vary depending on the type described above.

Symptoms may include:

  • muscle weakness and poor muscle tone
  • limited mobility
  • problem in reaching developmental milestones
  • breathing problems
  • feeding problems
  • abnormal tongue movements
  • scoliosis


SMA disease Causes

Spinal muscular atrophy is an inherited condition.

The gene affected is the SMN (survival of motor neuron).

Usually both parents must have a genetic mutation.


SMA disease Diagnosis

Spinal muscular atrophy is not easy to diagnose, because its symptoms may relate to other conditions as well.

There are several test that can confirm diagnosis.

  • Electromyography (EMG) test (to test the electrical activity of muscles)
  • MRI (magnetic resonance imaging)
  • blood test to look at the SMN gene


Spinal muscular atrophy treatment

In 2016 the U.S. Food and Drug Administration (FDA) approved the use of a new drug called nusinersen that has been shown to improve some motor function. The same drug was approved in October 2017 also in Italy.

Other treatment may be adopted to relieve specific symptoms.

From an orthopedic point of view, it may be suggested some orthosis that can help children to be as independent as possible in their daily activities such as leg braces, standing frames, canes, and walkers, wheelchairs…

Surgery may be needed to correct musculotendinous retraction and bones deformities.


About prof Portinaro’s experience with SMA disease

Prof. Portinaro performed more than 200 surgeries on children affected by SMA being a leading center in Italy for this pathology.

Prof. Portinaro and his team spend a large part of their work in international research projects to discover new treatments for childhood neuromotor disorders.

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