Pompe disease is a rare genetic condition that affects only 1 person in every 40,000 people in the United States, according to the National Institute of Neurological Disorders and Stroke (NINDS).

Pompe disease is often fatal, especially when diagnosed very early in life. This is because it harms the skeletal and heart muscles.

Having a specialized medical team can help treat and manage symptoms, leading to a better quality of life. Plus, new treatments and ongoing clinical trials may possibly lead to an improved outlook in the future.

Pompe disease may also be referred to as type II glycogen storage disease (GSD) or alpha-glucosidase (GAA) deficiency.

It occurs when there is a buildup of complex sugar, or glycogen, in the body’s cells. This prevents the cells from working properly, according to a 2014 research review.

More specifically, a deficiency in the enzyme GAA causes this buildup in organs and tissues.

When body processes are working as they should, GAA helps the body break down glycogen. However, people with Pompe disease have a mutation in the GAA gene, causing a reduction or complete elimination of the GAA enzyme.

Read on to learn more about the types of Pompe disease, the symptoms of each, how this rare genetic condition is treated, and the outlook.

There are two main types of Pompe disease: initial (early) onset and late-onset.

According to the National Organization for Rare Disorders, infantile onset is often associated with a faster disease progression and severity than late onset.

Infantile onset Pompe disease (IOPD)

IOPD, or early Pompe disease, consists of two types:

  • Classic onset: a baby displays symptoms within the first few months after birth
  • Non-classic onset: a baby tends to show signs of the rare disease closer to age 1

According to the NINDS, this type of Pompe disease is associated with a complete or near-complete deficiency of GAA. This means that the person has very little or none of the enzyme needed to help the body break down glycogen.

Late onset Pompe disease (LOPD)

LOPD, or juvenile and adult Pompe disease, is associated with a partial deficiency of GAA. Compared with IOPD, this type has a much longer range of when symptoms appear.

People with LOPD may begin noticing symptoms as early as their first decade of life or as late as their sixth decade, according to the NINDS.

This type of Pompe disease does not damage the heart like IOPD. Instead, individuals usually live with muscle weakness that progresses to respiratory weakness.

Children with early onset of Pompe disease begin displaying symptoms in the first months of life. Some of the more common signs of IOPD include:

  • trouble with feeding
  • weak muscles
  • heart concerns
  • enlarged heart
  • head lag
  • floppiness
  • lack of weight gain
  • hearing loss
  • complications from lung infections

Late onset of Pompe disease can also show symptoms later in life, during the juvenile or adult years. Symptoms of LOPD may include:

  • respiratory weakness
  • muscle weakness
  • muscle cramping
  • mobility difficulties
  • a gait (walking style) that’s different than usual
  • fatigue

Death from respiratory failure can occur in Pompe cases that last several years.

Pompe disease requires a specialized medical team. This team can treat and manage symptoms and offer ongoing care.

A treatment team may consist of a:

  • pediatrician
  • internist
  • orthopedist
  • cardiologist
  • neurologist
  • physical therapist
  • respiratory therapist
  • other healthcare professionals

Together, they will develop a disease-specific treatment plan that is supportive and aims to manage symptoms.

Enzyme replacement therapy (ERT)

The treatment of Pompe disease is disease-specific, symptomatic, and supportive. Enzyme replacement therapy (ERT) is an approved treatment for all people with Pompe disease. It involves the intravenous administration of a medication that helps reduce the buildup of glycogen. The Food and Drug Administration (FDA) approved Lumizyme in 2006 and Nexviazyme in 2021.

Supportive therapy may include respiratory therapy, physical therapy, and adequate nutritional therapy.

More specifically, the Food and Drug Administration (FDA) approved alglucosidase alfa (Myozyme) to treat IOPD, according to the NINDS.

For individuals of all ages, healthcare professionals have used Lumizyme to treat Pompe disease.

In 2021, the FDA also approved an enzyme replacement therapy called avalglucosidase alfa-ngpt (Nexviazyme) for people with LOPD. This is an IV medication that helps reduce the buildup of glycogen in the body.

Additional treatments

In addition to ERT, a treatment team may recommend supportive therapies like:

  • respiratory therapy
  • physiotherapy
  • occupational therapy
  • speech therapy
  • orthopedic devices

They may also suggest feeding therapies, such as a specialized higher calorie diet or a feeding tube if chewing and swallowing are concerns.

Gene therapy, which is considered an investigational therapy, is another option for treating Pompe disease.

According to NORD, one goal of gene therapy is to restore the body’s production and activity of the enzyme GAA in tissues like the diaphragm to help improve respiratory capacity.

Other gene therapies are in the clinical trial stage, with groups working to advance this type of treatment for Pompe disease.

Pompe disease is a genetic disease, so there is no way to prevent it from occurring. Pompe disease is often fatal, regardless of type, though treatment can help manage symptoms and extend life expectancy.

According to the NINDS, infants with classic Pompe disease may live fewer than 2 years and sometimes not even to year 1. If they do not receive ERT, their hearts will progressively thicken and enlarge, causing cardiorespiratory failure or respiratory infection.

Children with non-classic Pompe disease may live to early childhood.

LOPD, on the other hand, has a better outlook and a longer life expectancy, especially with the proper treatment.

Pompe disease is a complex inherited condition that requires a specialized team of healthcare professionals, who can treat and monitor symptoms as well as provide ongoing care. The younger a person’s age at diagnosis, the quicker the condition progresses.

If you have concerns that your child is displaying signs of Pompe disease, it’s critical to seek medical attention right away.

It may take some time to get a proper diagnosis, but the sooner treatment begins, the better the chances of holding off damage in the body.