Pompe Disease is a disease that is inherited in an autosomal recessive pattern, meaning both parents must have one copy of the mutated gene (genetics home reference, 2019). It effects 1 in 40 000 people (Sun, 2018) and the incidence of the disease varies among different ethnic groups with more frequency seen in Caucasian, Taiwanese, Chinese and Korean populations (Fukuhara et al, 2018). Symptoms associated with Pompe disease can vary widely depending on the age of onset and severity of the disease (the severity is directly related to the degree of deficiency of the required gene). There are two main types of pompe disease which may be considered prior to understanding symptoms; which is the early onset and late onset form of pompe disease (pompe disease information page, 2018). With early onset (infantile onset) the symptoms are seen as early as in the newborn stage. This form of pompe disease is the most severe as there tends to be a complete or near complete deficiency of the required gene (pompe disease information page, 2018). Some of the symptoms seen at this stage can include feeding problems, poor weight gain which is also symptomatic of “failure to thrive”, muscle weakness, enlarged tongue, respiratory difficulties (dyspnea) and lung infections (genetics home reference, 2019). Babies with pompe disease are likely to die of heart failure within the first year (Jeramillo, 2012). With late onset pompe disease there is a partial deficiency of the necessary gene. It is diagnosed from late childhood in to adulthood and is characterized as being more mild than early onset pompe disease and less likely to affect the heart (genetics home reference, 2019). Symptoms include progressive muscle weakness resulting in muscle loss, dysphagia, respiratory difficulties and scoliosis (Roberts, 2011).
Pompe disease is caused by a mutated gene called GAA. GAA works by providing the instructions to produce the enzyme acid-alpha glucosphate (also known as acid maltase). This enzyme is active in lysosomes (structures that act as recycling centres within the cell). The enzyme is responsible for breaking down glycogen into a simpler sugar- glucose (an important energy source for cells). To put it more simply, the GAA gene produces the enzyme acid-alpha glucosphate which then breaks down glycogen into glucose, which is necessary to fuel cells (genetics home reference, 2018).
The genetic mutation of the GAA gene affects function at the cellular level because the enzyme is unable to effectively break down glycogen into glucose. As a result, glycogen builds up to toxic levels and causes damage to organs and tissues of the body, with the muscle and skeletal tissues being particularly effected (Sun, 2018). The symptoms of pompe disease relate to the disrupted function at the cellular level because glycogen when converted by GAA into glucose will feed cells. Therefore, cellular function is disrupted with pompe disease (Sun, 2018) and the cells are deprived of the essential glucose necessary for their effective operations. Further, because there is no enzyme produced to breakdown glycogen, it accumulates everywhere within the cells of the heart and skeletal muscles (genetics home reference, 2018). Symptoms include progressive muscle weakness and respiratory issues, so we can understand just how this muscle weakness is caused in the body. We can understand how this is caused from understanding the importance of glucose in the cell and how a mutation in the GAA gene effects the ability to feed cells.
A person diagnosed with Pompe disease would be dealing with a progressive disease that gets worse over time. As an infant, they would deal with ‘failure to thrive’, which is to be below the norms on development, growth and weight and a high mortality rate. Later onset pompe disease would cause experiences such as dyspnea and frequent lung infections, they may perhaps have oxygen prescribed to assist with their breathing. With progressive weakness comes the possibility of walking and moving becoming increasingly difficult. They must adapt to a decrease in independence. They may need to use assistive devices that can make their lives significantly easier and walking aides such as wheelchairs and walkers may by necessary as well as the use of mechanical lifts. As dysphagia is a common symptom, they may need to modify their diet to softer foods. There is also a risk of depression and increased social isolation.
To be supportive to someone with pompe disease, it’s important to think of them as a person first. They are a person diagnosed with pompe disease. From there we would consider how their symptoms may affect their quality of life. It is important to promote a person’s independence on a safe and realistic scale. Pushing them to hard can increase risk for a fall. As such, it is best practice to use clear communication to offer support and assistance as needed. As there is a risk of increased social isolation, encouraging activities and interests is important, perhaps finding adaptable versions of those activities. Swimming, for example has adaptable options and is good for atrophied muscles. It is also important to encourage them to reach out to the many resources available to them, such as the United Pompe Foundation.
Pompe disease can have serious and fatal effects on the body. It is important to look forward to possible treatments, alongside symptoms management to improve quality of life. Recent advancements in enzyme replacement therapy have shown considerable success in slowing down the severity of the disease and has shown to prolong life in children (chien & hwu, 2007). In adults, an intravenous enzyme replacement therapy has been shown to improve the symptoms of the disease on a long-term basis (Merk, T, et al, 2009). Hopes for the future would be an increasingly improved enzyme replacement therapy that completely overcomes the enzyme deficiency in the body. A holistic approach alongside medical advancements offers the best route for improved quality of life.
- “Genetics Home Reference – NIH.” U.S. National Library of Medicine, National Institutes of Health, 22 Jan. 2019, ghr.nlm.nih.gov/.
- Pompe Disease Information Page. Retrieved from https://www.ninds.nih.gov/Disorders/All-Disorders/Pompe-Disease-Information-Page
- Fukuhara, Y., Fuji, N., Yamazaki, N., Hirakiyama, A., Kamioka, T., Seo, J., . . . Okuyama, T. (2018). A molecular analysis of the GAA gene and clinical spectrum in 38 patients with Pompe disease in Japan. Molecular Genetics and Metabolism Reports, 14, 3-9. doi:10.1016/j.ymgmr.2017.10.009
- Jaramillo, H. E. (2012). The cost-effectiveness of enzyme replacement therapy (ERT) for the infantile form of Pompe disease: Comparing a high-income country’s approach (England) to that of a middle-income one (Colombia). Revista De Salud Pública, 14(1), 143-155. doi:10.1590/s0124-00642012000100012
- Roberts, M., Kishnani, P. S., Ploeg, A. T., Müller-Felber, W., Merlini, L., Prasad, S., & Case, L. E. (2011). The prevalence and impact of scoliosis in Pompe disease: Lessons learned from the Pompe Registry. Molecular Genetics and Metabolism, 104(4), 574-582. doi:10.1016/j.ymgme.2011.08.011
- Sun, A. (2018). Lysosomal storage disease overview. Annals of Translational Medicine, 6(24). doi:10.21037/atm.2018.11.39
- Chien, Y, & Hwu, W. (2007). A review of treatment of Pompe Disease in infants. Biologics, 1(3), 195-203. Retrieved from, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2721312/
- Merk, T., Wibmer, T., Schumann, C., & Krüger, S. (2009). Glycogen storage disease type II (Pompe disease) – influence of enzyme replacement therapy in adults. European Journal of Neurology, 16(2), 274-277. doi:10.1111/j.1468-1331.2008.02377.x
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