Spinal Muscular Atrophy (Sma) Mutation Detection

Spinal muscular atrophy (SMA) is a genetic neuromuscular disease that causes muscles to weaken over time. Individuals infected with spinal muscular atrophy lose motor neurons (nerve cells in the spinal cord), which are responsible for controlling the movement of muscles. The absence of these neurons can cause muscles to not receive nerve signals that help with the movement.

An individual with this neuromuscular disease takes over two copies of the faulty SMN1 gene. Out of the two copies, one is inherited from the father and the other from the mother. An individual can carry one copy of the faulty gene that causes spinal muscular atrophy and be unaware of it.

This neurological disease has four major types – type 1, type 2, type 3, and type 4. In type 1, spinal muscular atrophy symptoms occur at the time of childbirth or within the first six months of an infant's life. Such infants have difficulty sucking and swallowing. They fail to meet basic milestones like sitting or keeping their heads up. Since their muscles weaken, they are at a high risk of respiratory infections and damaged lungs. Most children do not receive appropriate spinal muscular atrophy treatment and die before the second year of their birth.

Under type 2 of this disease, spinal muscular atrophy symptoms appear when the children are between six months to eighteen months. This particular type generally affects the lower legs. Kids infected with this type may practice sitting but cannot walk. Since it does not affect the children as severely, with appropriate spinal muscular atrophy treatment, most of them live till they are adults.

Under type 3, the spinal muscular atrophy symptoms occur after a child has lived for eighteen months. Some children or young adults don’t develop signs and symptoms of this neurological disease till they enter adulthood.

The symptoms include difficulty walking due to muscle weakness and recurring infections in the respiratory tract. These can worsen over time and affect the ability to perform functions like walking or standing. However, this type does not significantly threaten life expectancy like other types.

Type 4 spinal muscular atrophy does not occur until an individual reaches their mid-30s. Under this type, spinal muscular atrophy symptoms such as muscle weakness progress slowly. Hence, most patients with this type function well and can walk and live their whole lives.

At Apollo 24|7, you can opt for a spinal muscular atrophy test to:

• Detect the type of SMA gene inherited by you
• Find an appropriate spinal muscular atrophy treatment
   

Medically reviewed by Dr. Vijay Kishore Kondreddy, orthopedics from Apollo Hospitals Greams Road, Chennai.