Samantha was a couple of years old when her parents started to worry. A beautiful, happy child, Samantha started having trouble reaching her developmental milestones as quickly as her friends did.
She did not speak and only started walking at 18 months. Samantha didn’t look any different from the other children she played with, but her parents could tell that she was slowly falling behind and that something was wrong. Her doctors felt that she may be autistic, but they couldn’t explain her symptoms.
When Samantha turned five, she started having seizures. After seeing multiple specialists over those five years to try to figure out what was happening to their little girl, the Wallis family was fortunate enough to finally get a diagnosis. Samantha’s testing results showed that she was born with a rare genetic condition called GAMT deficiency.1
GAMT stands for guanidinoacetate methyltransferase. This is a chemical that is made in our livers. GAMT partners with another chemical called AGAT to make creatine. This creatine is used throughout our entire bodies to make the energy our bodies need to work. People who can’t make GAMT (like Samantha) have two problems going on in their bodies. First, they can’t make creatine. Without creatine, the body, and especially the brain, don’t have the energy they need to work properly. Secondly, the AGAT chemical has nothing to partner with, so it just keeps building up in the body. Unfortunately, a buildup of AGAT damages organs, especially the brain. Together, these issues lead to developmental delays, intellectual disability, epilepsy, and sometimes movement disorders.
Luckily, if a diagnosis of GAMT deficiency is made early in life, it is likely these problems can be avoided. By providing the child with creatine and reducing the AGAT chemical in the body, the issues that Samantha has lived with could be prevented. The key issue though, is that you need to start treatment early, especially before the AGAT has damaged the brain.2
In Samantha’s case, her diagnosis explained her symptoms and provided the Wallis family with an explanation and an avenue for improving her condition. Simply by changing her diet and adding a supplement, Samantha was able to stop the deterioration of her condition. Although much of the damage has already been done, Samantha is now able to speak a little and ride a bike with help. The fact that she said her first sentence at the age of nine was something her parents never thought they’d experience.
Since GAMT is a hereditary genetic disease, the Wallis family knew that there was a 25% chance of having another child with this condition. Fortunately, because of the known family history, they were able to have genetic testing performed on their babies at birth to look for this condition. One of their children, Louis, was tested and diagnosed with GAMT after his birth. Louis was lucky to get this early diagnosis because it meant that he could start treatment right away, before any of the problems associated with this disease started. Today, Louis is a healthy, happy, active boy who plays hockey, baseball, and video games. He does well in school and is expected to live a normal, healthy life.
The biggest worry about many of the hereditary disorders such as GAMT is that parents often do not know that their child has the condition until it is too late to prevent the long term damage. Fortunately, advances in newborn screening (NBS) and the availability of government screening programs mean millions of babies can get a healthier start in life.
In many countries around the world when a child is born, hospitals perform a routine prick on their heel and takes a few drops of blood. This blood will then be sent to a laboratory where they will perform a series of tests to look for a number of genetic diseases. In some regions this will include GAMT.
The goal behind this testing is to find babies who have one of the conditions they are looking for so that they can start managing it early. Early diagnoses of these conditions can lead to better outcomes for these children through medications, changes in diet and/or lifestyles, and/or early therapies. These early blood tests have been a part of the medical community’s toolbox to save children since the 1960s.3
Samantha’s brother Louis is a perfect example of why early detection, and therefore the benefit of NBS, is so important. Since Louis was diagnosed so early in life, he could start taking medication and make some simple changes to his diet, and thereby prevent any of the health concerns that his big sister Samantha struggled with.
Without NBS, children like Louis would have had to go on a diagnostic journey like Samantha, and might not have been diagnosed for many years, when the treatment would have been too late and their health would have suffered.
Over 13,000 newborns are diagnosed with medical disorders every year in the U.S. Luckily, NBS is able to help diagnose some of these conditions and prevent or lessen the irreversible damage they can cause.4 Depending upon where you live, NBS looks for 2–75 different conditions, with more being added every year. There is currently a movement towards considering using more detailed tests that could look at hundreds of conditions all at once. Called next-generation sequencing, this test has the capability of being faster, more accurate, and more comprehensive than the current technologies. Although there may still be some hurdles before this technology is used as a first-line test in the screening of newborns, such as cost and complexity, it holds the promise of helping more babies like Louis live a longer and healthier life.
Unfortunately, of the 134 million babies born in the world each year, only about one third of them receive screening of any type, and many babies are only screened for one or two conditions.3 As technologies get better, and politicians are convinced to devote more money and attention to the health of children, the hope is that more newborns like Louis will be saved, and more families like the Wallis’ can be helped.
To learn what they screen for in your state go to: Newborn Screening in Your State at newbornscreening.hrsa.gov
Revvity does not endorse or make recommendations with respect to research, medication, or treatments. All information presented is for informational purposes only and is not intended as medical advice. For country specific recommendations please consult your local health care professionals.
References
1. https://creatineinfo.org/rusp-presentation-heidi/ (accessed 22/11/2024)
2. Prospective identification by neonatal screening of patients with guanidinoacetate methyltransferase deficiency Mol Genet Metab. 2021 Sep-Oct;134(1-2):60-64. doi: 10.1016/j.ymgme.2021.07.012. Epub 2021 Jul 29.
3. The landscape for rare diseases in 2024, The Lancet Global Health, The Lancet Global Health, Volume 12, Issue 3, e34 https://www.thelancet.com/journals/langlo/article/PIIS2214-109X(24)00056-1/fulltext
4. https://blogs.cdc.gov/genomics/2019/11/18/public-health-perspectives/ (accessed 10/22/2024)
ABOUT THE AUTHORS:
Larry Prensky is the Senior Medical Affairs and Medical Education Manager at Revvity. He is a licensed genetic counselor and is a diplomate of the American Board of Genetic Counseling and the Canadian Association of Genetic Counsellors. Prior to working with Revvity, Larry was a clinical prenatal genetic counselor for over 20 years.
Mike Pattrick is the Reproductive Health Marketing Leader at Revvity, focused on maternal, fetal, and newborn health. He has worked within the healthcare industry for over 20 years in various roles, including: administration, sales and marketing. His experience has been gained through a variety of companies, from small venture set ups to large global corporations.
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