What is Pompe Disease?
Pompe disease is a rare disease that is inherited. A rare disease is a disease that only affects a small percentage of the world population. Pompe disease is also known as an acid alfa glucosidase (GAA) deficiency or type II glycogen storage disease (GSD). It leads to the breakdown of organs, tissues, and muscles. This breakdown primarily causes breathing problems and affects the liver, heart, and muscles. (NORD; Rare Disease Day; Reuser et al.)
There are three types of Pompe disease: Classic infantile-onset, non-classic infantile-onset, late-onset. In all three types, this disease occurs when the body stops producing GAA because of a flaw or mutation to the GAA gene. GAA is a protein responsible for breaking down complex sugars, like glycogen. Glycogen stores the largest supply of energy in the body. A lack of GAA leads to a buildup of glycogen. (Cleveland Clinic; Biology Dictionary; NIH; MedlinePlus)
Who is affected by Pompe Disease?
Since Pompe disease is a rare disease, it only affects a small percentage of the world population. Research shows that in the United States, 1 out of 40,000 individuals is living with Pompe disease. (Rare Disease Day; Cleveland Clinic)
Pompe disease can affect any individual whose two parents carry the mutated acid alfa glucosidase (GAA) gene. Parents may be carriers of Pompe disease without knowing it; parents who are carriers have one working GAA gene and one defective GAA gene. An individual must inherit both flawed genes to have Pompe disease. (NORD; Cleveland Clinic; WebMD)
Types of Pompe Disease
There are three types of Pompe disease. Each type affects different groups of individuals:
- Classic infantile-onset: This type affects newborn babies. The disease may appear during the first couple of months after birth.
- Non-classic infantile-onset: appears in one-year-old babies.
- Late-onset: appears throughout a wide range of ages. Some children, teenagers, young adults, and adults are affected by this Pompe disease type.
Signs and Characteristics
Individuals with Pompe disease may experience many of the same signs and symptoms; this depends on the type of Pompe disease they have.
- Classic infantile-onset: Babies with this type tend to encounter signs within the first few months after birth. Some signs and characteristics of classic infantile-onset are heart defects, enlarged liver, muscle weakness, poor muscle tone, failure to gain weight. Babies may also have trouble breathing, respiratory infections, feeding problems, and hearing problems. (Cleveland Clinic; Tarnopolsky et al.)
- Non-classic infantile-onset: Babies with this type of Pompe disease show signs around one year of age. These signs are related to the heart, respiratory system, motor skills, and muscles. One characteristic of this type is that babies may have an abnormally large heart. Babies may also have trouble rolling over and sitting. Muscle weakness may cause respiratory problems. (Cleveland Clinic; Tarnopolsky et al.)
- Late-onset: Anyone over the age of 1 may be affected by this type. Late-onset Pompe disease can be milder than the other two types. There are over 16 signs to look out for. These signs include weaker legs and trunk, breathing problems, enlarged heart, muscle pain, frequent falling over, lung infections, respiratory problems, weight loss, and difficulty hearing. (Cleveland Clinic; Tarnopolsky et al.)
To receive a proper diagnosis, an individual should consult these signs with a medical practitioner. (GARD)
Screening and Detection
Pompe disease is a genetic disease that is inherited. This disease is unpreventable, as a genetic mutation causes it. Genetic counselling may help couples and families who have the disease or are carriers for the disease by informing them of genetic risks before having a child and throughout pregnancy. Genetic counselling is an excellent source for information on genetic disorders. There are also several ways to screen for Pompe disease: Prenatal screening, newborn screening, carrier screening, biochemical testing, and molecular testing. (NORD; Cleveland Clinic)
This type of screening is available to those planning to conceive a child through in vitro fertilization (IVF). IVF is a series of medical procedures where a woman's egg and man's sperm are fertilized outside a woman's body. Medical practitioners may screen embryos for any genetic flaws and complications before being implanted to possibly prevent genetic mutations. (MedlinePlus; MayoClinic)
Medical practitioners may detect Pompe disease before a child's birth through prenatal screening. Prenatal screening may be done if a fetus is at a high risk of acquiring Pompe disease from the parents. This screening occurs between the 10 to 20-week pregnancy mark by extracting a DNA sample through amniocentesis or chorionic villus sampling. Amniocentesis sampling happens when a physician removes some of the protective liquid surrounding a developing fetus. Chorionic villus sampling is done by a physician who takes a small sample from the mother's placenta. The placenta is a temporary organ that provides the exchange of oxygen, nutrients, and waste to and from the growing fetus. This DNA sample is taken to measure acid alfa glucosidase (GAA) activity. Pompe disease occurs when the body stops producing GAA because of a flaw or mutation to the GAA gene. Both amniocentesis and chorionic villus sampling may cause miscarriage. (Kids Health; Taglia et al; MayoClinic; NORD)
Newborn babies may be screened for Pompe disease using dried blood spot testing. This kind of testing only requires a low blood volume, unlike other blood tests. This type of screening is done by pricking a newborn's heel and collecting a small quantity of blood on filter paper. Physicians count GAA activity by studying the blood sample. (NORD; Taglia et al; CATIE)
Physicians may screen for Pompe disease by looking at a patient's genetic history. This screening involves evaluating a patient's parent and family history. A patient is at a higher risk for having the disease or being a carrier if a patient has a family member with Pompe disease. Patients with a family history of Pompe disease can do carrier screening. This type of screening involves biochemical testing and molecular testing. (MedlinePlus; Taglia et al; NORD)
Other Types of Screening
There are other kinds of screening that do not involve DNA testing. These screening types determine symptoms relating to the lungs, heart, and muscle function. Healthcare practitioners use muscle imaging by magnetic resonance (MRI) to assess muscle function and damage. Chest x-ray, electrocardiography (ECG), and ultrasound imaging looks at a person's heart and heart function. (NORD)
Pompe Disease Management
Enzyme Replacement Therapy (ERT)
ERT is distributed to a patient by an injection administered into a vein. The injection contains an enzyme that is genetically engineered and mimics acid alfa glucosidase (GAA). Pompe disease occurs when a person's body stops producing GAA because of a flaw or mutation to the GAA gene. ERT is the only treatment that has proven to be efficient in treating Pompe disease.
Researchers and physicians agree that ERT may extend a person's life expectancy. Although ERT is an effective treatment, it may not entirely cure a patient or completely relieve Pompe disease symptoms. (NORD)
There may be side effects to ERT. Some of these side effects include allergic reactions, low blood oxygen levels, flushed skin, elevated heart rate, headache, dizziness, and nausea. (Lumizyme; EMA; Medscape)
There are supportive therapies that do not directly treat Pompe disease but help manage and relieve symptoms. Some of these supportive therapies include physical therapy, mechanical ventilation, physiotherapy, assistive devices, speech therapy, orthopedic devices, surgery, and nutrition plans (NORD)
- Physical therapy is a supportive therapy that helps patients strengthen their respiratory muscles. Pompe disease may create respiratory problems; physical therapy can be beneficial because of this. (NORD)
- Mechanical ventilation: If physical therapy is not enough, patients can use mechanical ventilation in addition to physical therapy. A patient may use invasive or noninvasive mechanical ventilators to help them breathe during various times of the day. (NORD; Tarnopolsky et al.)
- Physiotherapy is a supportive therapy that, when done correctly, helps a patient improve and maintain muscle strength. Muscle loss is one of the characteristics of this disease. (NORD; Physiopedia)
- Assistive devices are devices that help a person perform daily activities. Since patients with Pompe disease may experience frequent falling over and weaker legs, assistive devices like canes, walkers, and wheelchairs can help patients. (NORD; NIH)
- Orthopedic devices help prevent the loss of muscles and connective tissue in the feet, ankles, hands, and fingers. (NORD)
- Speech therapy may help some patients to better articulate their words after experiencing a decrease in facial muscle strength. (NORD)
- Surgery: Patients may require surgery if they experience orthopedic problems, such as scoliosis, shrinkage of muscle or tendons, and foot deformities that orthopedic devices cannot manage. (NORD)
- Nutrition plans made for patients by physicians are essential when managing Pompe disease; this is because facial muscles used for chewing and swallowing may weaken. Some patients may need a specialized diet to help them chew and swallow. Additionally, feeding tubes may be inserted into some babies and children, depending on their facial muscle strength. (NORD)
Living with Pompe Disease
Daily management for those living with Pompe disease varies from person to person.
Here are some points for patients and caregivers to keep in mind:
- Most patients will have to adjust their daily routines and plan tasks ahead of time to relieve stress.
- If patients have nutrition plans, they must modify their diet and prepare meals differently. The texture and thickness of food may need to be changed to help patients swallow.
- If patients cannot obtain essential vitamins through their nutrition, physicians may recommend a vitamin supplement.
- Patients who struggle with accessibility and daily activities can use orthopedic devices, canes, walkers, and wheelchairs to help them move around.
- Exercise routines will have to change to accommodate muscle loss and mobility changes.
- Patients can continue to practice interests, hobbies, and social activities as long as physicians approve of these activities.
- Physicians may prescribe Myozyme or Lumizyme to treat Pompe disease. Physicians typically apply these medications through an injection every two weeks.
(POMPE; NORD; RxList; Lumizyme)
- Classic infantile-onset: Babies with classic infantile-onset are at the most risk. Babies may die before the age of one if Pompe disease is not detected and they do not receive treatment and therapy. (NIH)
- Non-classic infantile-onset: Babies with non-classic infantile-onset are also at high risk. Babies may die before early childhood if Pompe disease is not detected and they do not receive treatment and therapy. (NIH)
- Late-onset: Patients with late-onset may have a higher chance of survival if Pompe disease is detected and treated. This is because late-onset Pompe disease develops at a slower rate. (NIH)
Rare Disease Challenges
Pompe disease is a rare disease. Rare diseases are constantly evolving and may worsen an individual's health over time. Approximately 3.5% to 5.9% of the total world population live with a rare disease. Since rare diseases only affect a small part of the world population, there is not enough scientific knowledge on research and treatments related to rare diseases. However, researchers and physicians constantly search for new information to treat rare diseases, like Pompe disease. (Orphanet Canada; Rare Disease Day)
To learn more about rare diseases, click here.
Although Pompe disease can be challenging, there are groups and organizations that support those living with Pompe disease. Support groups are a great way to meet others living with the same or similar conditions. Support groups may also be a good source of information. (WebMD)
Living with Pompe disease can impact an individual's mental health. Mental health can be affected as patients may feel stress, anxiety, and depression in addition to the physical symptoms they are already experiencing. Caregivers, family, and friends of an individual living with Pompe disease may also experience mental health issues. (CORD)
Some signs to look out for are:
- Appetite changes
- Insomnia (trouble falling or staying asleep
- Hypersomnia (too much sleep)
- Low productivity
- A dependence on alcohol or smoking
- Suicidal thoughts
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