Juvenile primary lateral sclerosis

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at September 26, 2016
StartDiseasesJuvenile primary lateral sclerosis

Individuals with juvenile primary lateral sclerosis or JPLS experience muscle weakness and stiffness in their arms and legs. Juvenile primary lateral sclerosis is a type of motor neuron disease. Though confused with amyotrophic lateral sclerosis (also known as ALS or Lou Gehrig's disease), it is less severe and progresses more slowly.

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Definition & Facts

Juvenile primary lateral sclerosis is a genetic disorder that causes the voluntary muscles, or muscles which an individual controls, to become weak or stiff. These are muscles within the arms, legs, and tongue that a person uses to move, pick things up, or talk. 

Unlike primary lateral sclerosis which affects adults, juvenile primary lateral sclerosis affects children and is inherited via an autosomal recessive inheritance pattern.

Symptoms & Complaints

Juvenile primary lateral sclerosis usually first begins in early childhood and often takes years to progress. There are a number of symptoms linked to JPLS, including:

Causes 

The cause of juvenile primary lateral sclerosis is a genetic mutation called ALS2. It is unknown exactly how this mutated gene causes JPLS, but researchers do know that the gene has the responsibility of giving instructions that are used to create alsin, which is a protein, in motor neuron cells. Motor neuron cells are cells in the brain and spinal cord that help to control muscles.

When the gene is mutated, the instructions that the gene gives are changed. This change makes the alsin protein unstable and not work properly, leading to impairment in the way that the muscles should normally function. 

In order for a child to have this gene mutation, both parents must carry the gene. Even if the parents did not have juvenile primary lateral sclerosis themselves, they can still carry the gene and then pass it on to their children.

Diagnosis & Tests

When any of the symptoms for JPLS is noticed, it is important to get the child to the doctor as soon as possible. There is not just one test that will be done in order to determine if JPLS is the cause of the symptoms. JPLS is actually similar in symptoms to other diseases, so several tests will need to be done in order to rule out other diseases. 

The doctor will first go through the patient's medical history and the medical history of the family as well. A neurological examination to assess motor and sensory responses will be completed and then a number of other tests may be completed including:

  • Blood tests-This will be done to check for any type of infection or other possible causes of the muscle weakness.
  • Electromyogram or EMG-The EMG consists of a needle electrode being inserted into different muscles in the body. The test will check the electrical activity of the muscles when they are moving and when they are resting. This test will help show if the patient is suffering from JPLS or amyotrophic lateral sclerosis, which is similar to JPLS.
  • Magnetic resonance imaging (MRI)-An MRI may be completed in order to look for degeneration of the nerve cells. It may also be used to look for other potential causes for the symptoms.
  • Spinal tap (also known as a lumbar puncture). A small sample of cerebrospinal fluid is removed from the spinal canal in order to be analyzed by a laboratory. This test is completed in order to rule out some types of infection, multiple sclerosis, and others.

Once the testing has been completed, and all other causes have been ruled out, there may be a diagnosis of juvenile primary lateral sclerosis. Because of how similar JPLS is to ALS, a doctor may wait three to four years before JPLS is diagnosed. The treatment can begin immediately even without the diagnosis.

Treatment & Therapy

Unfortunately, there is no cure for juvenile primary lateral sclerosis. The treatment options that are available are used to relieve the symptoms of the disease and to preserve or improve the patient's function. The treatment that is used includes:

  • Medication - Medications, such as tizanidine, baclofen, or clonazepam, may be prescribed to help relieve the muscle spasms that a patient may have. These medications will be taken orally as prescribed. If taking these medications orally is not relieve the muscle spasms, then the doctor may want to administer medication through an intrathecal pump, which is a pump that is surgically implanted in the patient and that will bring baclofen directly into the cerebrospinal fluid.
  • Speech therapy- If the muscles in a patient's face are affected by the disease, then speech therapy may be used in order to help the patient communicate.
  • Physical therapy- Exercises are used to stretch and strengthen the patient's muscles. The therapy also helps maintain the range of motion, flexibility, and mobility of the joints.
  • Assistive devices - If JPLS continues to progress and makes it difficult for the patient to walk and get around on their own, assistive devices may be used, such as an assistive cane, assistive walker, or wheelchair.

Prevention & Prophylaxis

There is currently no cure for juvenile primary lateral sclerosis. It is a rare genetic disease and both parents have to carry the gene, so parents may opt for genetic testing in order to assess the risk of passing on the mutated gene for JPLS to the child.