Pompe disease is a very rare, thought to be 1 in 40,000 live births (in infant onset 1 in 138,000 and in juvenile and adult onset 1 in 57,000). Pompe disease is normally split into three types; infant, juvenile or adult onset and the classification is dependant on the amount of enzyme naturally produced by the patient.
Infants born with Pompe disease may produce very little or no enzyme and may die within weeks of birth if they are not given immediate enzyme replacement therapy.
Pompe disease is caused by a shortage of acid alpha-glucosidase whereby the lysosomal degradation of glycogen is hampered and glycogen accumulates inside the lysosomes. The lysosomes become unusually large and fuse to form large lysosomal spaces that eventually occupy a substantial part of the total cellular volume. The ensuing cellular pathology, predominantly manifesting in muscle cells as loss of architecture, ultimately leads to skeletal muscle weakness and clinical symptoms. (Pompe Disease Martina Baethmann UniMed)
Babies born with infantile onset Pompe may experience rapid progressive muscle damage, muscle weakness, Cardiomyopathy and premature death.
This is Nate. He was diagnosed with Pompe at 7 months of age. Nate’s symptoms included an enlarged heart, low muscle tone, muscle weakness, swallowing difficulties and delays in meeting milestones. Sadly Nate passed away in 2016 at 32 months old.
However with newborn screening Nate’s Pompe disease would have been detected at birth. Nate would have started treatment straight away.
It is thought that 3 Pompe infants like Nate, are born every year in Australia. Some babies survive the time required to be diagnosed and started on treatment. Many don’t.
Due to Pompe being so rare very few doctors in Australia have even seen another patient. This means it may require multiple referrals from doctors to specialists before Pompe can be diagnosed. Testing for Pompe is now relatively simple and can be undertaken in a few days. However, with the number of diseases with very similar symptoms testing can often be tragically delayed, particularly when the patient is outside of the metropolitan areas.
The Australian Pompe Association understands that the tests used in newborn screening have a potential to have false positives. Therefore the Australian Pompe Association would recommend that GAA DBS assay testing, or genetic testing, be undertaken to give a final diagnosis.
Incidence and Tragedies
In the last 5 years, the Australian Pompe Association is aware of 5 infants passing away in their first few months of life. Newborn screening of Pompe would have enabled these babies to have started treatment within days of birth rather than the typical delay of three – six months, or more, once symptoms were observed and diagnosis was sought.
Why is Pompe different?
Pompe disease is one of the few rare diseases there is a treatment for. The sooner the baby can receive treatment the better the outcomes for that child and their family.
With an incidence of 1 in 138,000 and an average birth rate of 305,377 per year (ABS data for 2015) three Pompe babies will be born every year in Australia. These children and their parents need our help to ensure that they have the best chance of life.
This incidence of birth would also suggest that 10 babies have passed away in Australia in the last 5 years without ever being diagnosed prior to post mortem.
Experience Overseas and Reports in Australia
Screening for Pompe is becoming very common, with 8 American states including California and Washington state currently screening for Pompe. To compare with Australia, California currently screens for 59 disorders on their newborn screening, whilst NSW only screens for 36. It is also important to note that newborn screening In NSW has not added a new disease to the list since the year 2000.
A Study in Taiwan (pre 2008) of 132,532 babies found 4 Pompe babies. Their diagnosis was significantly advanced by 3- 6 months with a much better outcome. Taiwan remains the gold standard for Newborn screening as they are able to diagnose and get babies into treatment within 5 days of birth here in Australia it is typically 3 months and 6 months if the child lives outside of the metropolitan areas.
A 2012 Queensland report on Lysosomal disorders revived the incidence and benefits of new born screening and found significant benefits in testing.
In the event that Newborn screening shows that a child has late onset Pompe disease which can manifest at any time in life, and as the pathway to diagnosis continues to be very difficult in later life, the Australian Pompe Association would strongly recommend that the families of asymptomic babies have the choice to be advised of their babies’ juvenile or adult onset Pompe diagnosis.
IMPORTANT: This information is intended to provide general information in regard to the matter covered. It is provided as a public service by the Australian Pompe Association. Medicine is constantly changing and humane error and changes in practice make it impossible to certify the accuracy of such complex material. Confirmation of this information from your doctor or medical practitioner is required.