Spinal muscular atrophy

Symptoms of spinal muscular atrophy

The symptoms of spinal muscular atrophy (SMA) and when they first appear depend on the type of SMA you have.

Typical symptoms include:

• floppy or weak arms and legs
• movement problems – such as difficulty sitting up, crawling or walking
• twitching or shaking muscles (tremors)
• bone and joint problems – such as an unusually curved spine (scoliosis)
• swallowing problems
• difficulty breathing

SMA doesn't affect intelligence or cause learning disabilities.

Types of SMA

Spinal muscular atrophy (SMA) is often grouped into types. 

These are based on the age that symptoms begin and how they affect sitting, standing and walking.

The main types are:

• type 1 – babies less than six months old
• type 2 – babies and toddlers aged six to 17 months old
• type 3 – children and teenagers from 18 months to 17 years old
• type 4 – adults 18 years and  older

Although spinal muscular atrophy (SMA) affects everyone differently, some types are considered more severe and can affect how long someone lives.

SMA is usually more severe the earlier symptoms begin. However, the outlook for each type depends on a person's symptoms and how well treatment works.

Treatments for SMA

There is no cure for SMA, but treatment and support is available to manage the symptoms and help people with SMA have the best possible quality of life.

Treatment may involve:

• exercises and equipment to help with movement and breathing
• feeding tubes and diet advice
• braces or surgery to treat problems with the spine or joints

A range of healthcare professionals may be involved in your care, including: 

• specialist doctors
• physiotherapists
• occupational therapists
• speech and language therapists

Tests for SMA

The genetic problem that causes SMA is passed on to a child by their parents.

Speak to your GP if you're planning a pregnancy and:

• you've had a child with SMA before
• you have a history of the condition in your family
• your partner has a history of the condition in their family

Your GP may refer you to hospital, for specialist advice, to discuss the risk of the condition affecting a future pregnancy and any tests you can have.

If you're pregnant and there's a chance your baby could have SMA, tests can be carried out to check if they'll be born with the condition. 

Tests can also be done after birth to diagnose SMA in children and adults.

In most cases, a child can only be born with SMA if both of their parents have a faulty gene that causes the condition.

The parents won't usually have SMA themselves, which is known as being a "carrier".

Some rarer types of SMA are inherited in a slightly different way, or may not be passed on at all.

• Spinal muscular atrophy

More useful links

• How to use your health services
• SMA Support UK