What is SMA?

Here are some quick facts about spinal muscular atrophy (SMA).

SMA is an inherited genetic disease. It occurs when a child inherits two mutated copies of the survival motor neuron 1 (SMN1) gene, one from each parent (autosomal recessive inheritance).

If a child only inherits one mutated copy of the SMN1 gene, he or she becomes a carrier of the recessive gene.

On average, one in 50 people carry the mutated SMN1 gene.

In Malaysia, 50 babies are estimated to be born with SMA every year.

SMA is a neuromuscular disorder, affecting the motor nerves in the body.

It causes the muscles in the body to become progressively weaker.

It affects essential physical activities like breathing and chewing/swallowing, as well as all movement, including head control and crawling/walking.

SMA does not affect the child’s intelligence or senses.

SMA can be categorized into four clinical types:

SMA Type 1

Most common and severe type.
Symptoms appear at birth or within first few months of life.
Patients have difficulty breathing and eating.
Usually do not live beyond two years of age.

SMA Type 2

Symptoms appear between six to 24 months of age.
Patients can sit by themselves, but are unable to stand or walk on their own.
Life expectancy ranges from childhood to adulthood, depending on the severity of their condition.