Is Spinal Muscular Atrophy the Same as Spina Bifida?

Although spinal muscular atrophy and spina bifida have some similar symptoms, they are different conditions.

If you’ve wondered if spinal muscular atrophy is the same as spina bifida, you aren’t alone. It’s easy to confuse these two conditions since they both involve the spine. But spinal muscular atrophy and spina bifida are two distinct conditions.

Spinal muscular atrophy (SMA) is a category of inherited diseases that cause injury to the brain and spinal cord, affecting motor neurons and leading to problems with muscle movement, as well as difficulty breathing and swallowing.

Spina bifida also involves the spine, but it begins during fetal development, when the neural tube, cells that form the brain and spinal cord, doesn’t close all the way, often resulting in injury to the spine and spinal nerves. Spina bifida can cause:

• muscle weakness (hypotonia)
• muscle rigidity (hypertonia)
• paralysis
• trouble breathing
• learning disabilities
• bowel and bladder problems

Spinal muscular atrophy and spina bifida aren’t the same conditions, but they share some similar causes, symptoms, and treatments.

Causes

Spinal muscular atrophy and spina bifida both have heredity as a cause or potential cause. Spinal muscular atrophy is usually caused by a mutation in a gene called survival motor neuron gene 1 (SMN1) . When children are born with this mutation, they lack a protein necessary for the functioning of many types of motor neurons.

Experts aren’t entirely sure what causes spina bifida but believe it’s a combination of heredity, nutritional deficiencies, and environmental hazards.

Symptoms

Both spinal muscular atrophy and spina bifida may affect the brain and spinal cord. There are several types of spinal muscular atrophy and spina bifida, each causing different symptoms. But there are some symptoms that both conditions may share.

For example, both spinal muscular atrophy and spina bifida can cause muscle weakness and decreased mobility. People with these conditions may have trouble walking and may need walking assistance. Both conditions also can cause difficulty breathing and trouble swallowing.

Treatment

The medical procedures and medications used to treat spinal muscular atrophy and spina bifida are different, but some of the rehabilitation options overlap. People with spinal muscular atrophy and spina bifida may need physical therapy and may require walking aids, such as wheelchairs, braces, or walkers.

Although spinal muscular atrophy and spina bifida both involve the spinal cord and nervous system, they are more dissimilar than similar.

Causes

There are four types of spinal muscular atrophy, each with somewhat different causes, but all are caused by genetic mutations that lead to insufficient levels of a protein (SMN) that affects the way muscles function.

While spina bifida likely has genetic causes as well, it’s unclear what these causes are. Spina bifida is more closely associated with nutritional deficiencies during pregnancy, particularly folic acid deficiencies.

Symptoms

Spinal muscular atrophy and spina bifida both affect the spinal cord, and while they have a few symptoms in common, they have many differing symptoms.

There are several types of spinal muscular atrophy, and each presents with different symptoms and severity.

The most severe type (Type 0) causes weak muscle tone, reduced mobility, and trouble swallowing and breathing; it has a poor prognosis, usually resulting in death before 2 years of age. Types 3 and 4 have milder symptoms, and people with these types usually have typical lifespans.

Similar to spinal muscular atrophy, there are several different types of spina bifida, each with varying symptoms. Some types, such as occulta, may cause no symptoms at all. Other types may cause:

• weak muscles
• bowel and bladder incontinence
• loss of sensation in the groin and legs
• learning disabilities

Treatment

Both spinal muscular atrophy and spina bifida can be treated. However, the treatments for each condition are different.

The main way that spinal muscular atrophy is treated is with medication. Although the condition can’t be cured, it may be managed with medications that increase SMN proteins, as well as different types of gene therapy.

Not everyone with spina bifida needs treatment. When treatment is required, it usually involves surgery. Surgery is typically done after a baby is born, but sometimes it’s done while the baby is still in the womb. Surgery usually involves closing the gaps in the spine.