Introduction

Pompe (pronounced “pom-pay”) Disease is a progressive, inherited condition caused by the accumulation of a sugar called Glycogen within body tissues, impairing their function. It is a rare condition, affecting around one in 40,000 people. While the condition is not curable, there are treatments available which allow individuals with Pompe disease to maintain a good quality of life and independence.³

What is Pompe Disease?

 Pompe Disease occurs when a child inherits a mutation in the GAA gene, from their parents. The GAA gene is responsible for the production of an enzyme called Alpha-Glucosidase (an enzyme is a protein that speeds up many processes within the body). In the absence of this enzyme, glycogen starts accumulating within the lysosomes found in muscle cells. Lysosomes are small structures found within cells that are responsible for breaking down waste products.^3,16 Eventually, so much glycogen builds up inside these lysosomes that they break apart and destroy themselves.³

Inheriting Pompe Disease

Pompe Disease is inherited in an Autosomal Recessive manner, meaning that in order for an individual to be diagnosed with this condition, they need to inherit the mutated gene from both parents.¹

This means that the parents of people with Pompe disease may have the disease themselves.¹ If they do not have Pompe Disease, they must have a copy of the mutated gene in their DNA which has not affected them but that they passed down to the child.¹ People with only one mutated gene may not have the disease, and may not even know that they carry the mutated gene, but can still pass it on to their children.⁶

Types of Pompe Disease

There are two kinds of Pompe Disease: Infantile Pompe Disease and Late Onset Pompe Disease.

Infantile Pompe Disease

Infantile Pompe Disease is the most severe form of Pompe Disease. It causes:^1,3

• Cardiomegaly: a condition where the heart becomes enlarged. This gets rapidly worse in Pompe Disease
• Breathing problems
• Hypotonia: where a person becomes “weak” and “floppy”
• Hepatomegaly: where the liver becomes larger than normal

This disease was first identified by Johannes Pompe, who gave the disease his name. Most children with Infantile Pompe Disease die within their first year of life if they do not receive treatment.³

Late-Onset Pompe Disease

The symptoms of Late Onset Pompe Disease become noticeable later than infantile Pompe disease, manifesting any time between childhood and late adulthood. Late Onset Pompe Disease causes gradual worsening weakness of the muscles around the shoulders and pelvis, causing the limbs to become “floppy”.³

Who is at risk?

Some ethnic groups are more likely to have Pompe Disease than others such as: 

• People of Israeli descent
• African American people
• Taiwanese people
• Dutch people

Symptoms

Infantile Pompe disease can cause different symptoms than the late-onset Pompe disease.⁷

Symptoms of Infantile Pompe Disease

The symptoms of Infantile Pompe Disease include:^7,8 

• Larger than normal tongue
• Difficulty feeding
• Inability to support the head
• Difficulty speaking and swallowing due to weak facial muscles
• Difficulty gaining weight
• Larger than normal heart
• Difficulty breathing
• Weak muscles

Symptoms of late-onset Pompe Disease

People with late onset Pompe disease experience gradual weakening of muscles over the years, causing difficulty breathing.

The weakness also affects the legs, interfering with activities such as walking and other exercise.³

One-third of patients with Pompe disease have Scoliosis, a condition where the spine is not straight but twisted to one side.^9,10 Sometimes a back brace or surgery is needed to correct this.¹⁰

Diagnosis

Pompe Disease can be diagnosed with the help of a Newborn Blood Spot test. This test is done by a health worker when the child is five days old.¹¹ They carefully prick the skin on the baby’s heel and collect four drops of blood which are then tested for genetic conditions like Pompe Disease.¹¹

One of the things that is examined by the blood spot test is the levels of acid alpha-glucosidase enzyme in the body.³ If the acid alpha-glucosidase levels are lower than they should be, genetic sequencing will be done to confirm the presence of Pompe Disease.³

Genetic testing requires a small sample of either blood or saliva which is then sent to a lab for examination of mutated GAA gene.¹²

Treatment

Enzyme replacement therapy

Enzyme Replacement Therapy is a treatment where you are given medicine to replace the enzymes that your body cannot produce on its own.¹

These enzymes are given by intravenous infusion (via a tube directly into your vein), usually once a fortnight.^1,13 It usually takes four or five hours and some patients learn to do this themselves at home, reducing the time spent with the healthcare provider.¹

Supportive treatment

Due to the variety of symptoms caused by Pompe disease, people with the condition often require other therapies along with enzyme replacement therapy. Some of these are listed below:

Genetic counselors

If your doctor suspects Pompe disease, they may refer you to a genetic counsellor.³ Genetic counsellors help patients and their families understand the test results, the chances of passing on health problems to children, treatment options if you or a child have inherited the condition, and the support available in case of testing positive.¹²

Physical therapy

As discussed above, Pompe disease can cause problems with the muscles. Therefore, it is important to keep the muscles as healthy and strong as possible, so your doctor may refer you to a physical therapist.³

Nutritionist

Recent research has found that high-protein diets (combined with a suitable exercise regimen) can help people with Pompe disease improve their quality of life.¹⁴ Your doctor may refer you to a nutritionist or dietician so that they can help you follow the diet that suits you best.³

Speech therapy

Due to the weakness of muscles in the face as mentioned above, some children with Pompe disease may struggle with speaking certain words. Your healthcare provider may refer you to a speech therapist to help with this.⁸

Respiratory therapy

People with Pompe disease often have trouble breathing so, your health team may work with a Respiratory Therapist to help the patient as much as possible.¹⁵ The Respiratory Therapist may provide you with equipment, exercises, and support to help you maintain your quality of life.¹⁵

Smoking help

It is recommended that people with Pompe Disease do not smoke, or quit smoking, as Pompe disease problems can cause problems breathing which can be made worse by smoking.¹

Summary

Pompe Disease is a rare hereditary condition caused by a mutated GAA gene responsible for the production of an enzyme called alpha-glucosidase. The absence of this enzyme leads to excess glycogen deposition in muscles, causing damage and destruction of muscle fibres. If left untreated, this condition can result in death. However, there are treatments such as Enzyme Replacement Therapy available to help people with Pompe Disease.

If you think that you or someone you know may have Pompe Disease, it is important to make an appointment with your general physician as early diagnosis and treatment are the best way to help.