Understanding Pompe disease

When you’re managing Pompe disease, the value of information shouldn’t be underestimated. Learn what Pompe disease is, what causes it, and what symptoms it may lead to.

Ryan

Diagnosed with LOPD at age 31

Pompe disease at a glance

2 subtypes

A rare,

autosomal recessive

disease that can be classified into two subtypes:

IOPD and LOPD

Caused by

variations

in the acid alpha-glucosidase (GAA) gene, leading to a buildup of

glycogen

in the muscles

An inherited condition that can cause varying levels of disease severity, depending on how much GAA enzyme activity is present

What is Pompe disease?

Pompe disease is a rare,

lysosomal disease

causing muscular weakness that eventually leads to impaired mobility and breathing problems. Pompe disease is also referred to as acid maltase deficiency and glycogen storage disease type II.

Pompe disease is caused by variations in the acid alpha-glucosidase (GAA)

gene

These variations lead to a deficiency in GAA protein, which limits the body’s ability to break down glycogen in the

lysosomes

This buildup of glycogen damages the body’s muscles, affecting mobility. As the muscles that control breathing become affected, respiratory problems can begin.

1 in 28k Pompe Prevalence in the U.S.

In the United States, an estimated 1 out of every 28,000 babies are born with Pompe disease today.

Glycogen: the real culprit

Although Pompe is caused by GAA gene

variations

glycogen is the real culprit. As

glycogen

steadily builds up in the

lysosomes

of muscle tissue, it causes tissue and organ damage, and eventually leads to

progressive

muscle deterioration. When the muscles that control breathing—such as the

diaphragm

and the

intercostal muscles

to deteriorate, respiratory problems may occur.

Because of this gradual loss of muscle control, many people with Pompe may eventually require assistive devices like canes, walkers, and wheelchairs over time. A ventilator may also be required to assist breathing, while any issues with swallowing or eating may eventually require the use of feeding tubes.

IOPD and LOPD

Pompe disease is classified into two subtypes: infantile-onset Pompe disease (IOPD) and late-onset Pompe disease (LOPD). In IOPD, symptoms typically appear during the first year of life and tend to progress very quickly.

With LOPD, symptoms may not be apparent right away, and can mimic those of other disorders. Symptoms of LOPD can present at any time, and most commonly consist of muscle weakness and breathing problems. But LOPD can also cause a range of other symptoms, including fatigue, digestive problems, difficulties with talking and chewing, and more. This can make LOPD very difficult to diagnose.

The importance of enzyme activity

People with IOPD have very low levels of GAA

enzyme

activity, with typically less than 1% of what’s considered normal. On the other hand, the levels of GAA enzyme activity can vary over a wide range (2% to 40% of what’s considered normal) in individuals with LOPD. That’s why no two people experience Pompe the same way.

What exactly does this mean? In terms of disease progression, it means a lot. The amount of GAA enzyme activity can impact how severe Pompe can become for each individual.

How is Pompe inherited?

normal GAA gene

mutated GAA gene

Every person inherits one copy of a gene from their father and one copy from their mother. Pompe is an

autosomal recessive

disorder, meaning that a mutated version of the GAA

gene

must be inherited from both parents. If one of the two inherited GAA genes is normal, a person will not have Pompe disease, but would be considered a “carrier.”

Pompe disease carriers usually do not have any signs or symptoms of the disease. However, they can pass it down to their children. Whether or not a person develops Pompe disease depends on the genes they inherited from both their parents.

For in-depth information about how Pompe affects families, download the Pompe visual guide below.

Download the Pompe visual guide

Find easy-to-understand information about Pompe disease.

Download

Early detection is everything

Pompe disease can be very difficult to diagnose. And while the presence of symptoms can help to establish a diagnosis, GAA enzyme and carrier identification screenings are required to confirm it. Newborn screening can lead to earlier detection and treatment, which is of utmost importance. Without proper treatment, most people with IOPD will succumb to the disease before the age of 1 year.

Your next chapter begins with you

When it comes to managing Pompe disease, there’s no one-size-fits-all approach. The best strategy for one person might not make sense for you, and vice versa. Individual choices should be made together with your healthcare team, and with both short-term and long-term goals in mind.

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