What is Global Metabolomic Assisted Pathway Screening (Global MAPS®)?
Patients and families often ask their healthcare providers about whether neuromuscular disorders are genetic. The short answer is yes – many neuromuscular disorders are caused by genetic mutations that affect the nerves and muscles. This blog will dive deeper into this topic and explain how genetic testing can help diagnose and inform treatment for these conditions.
Neuromuscular disorders are a group of conditions that affect the nerves that control voluntary muscles. There are many different types of neuromuscular disorders, but some of the most well-known ones include muscular dystrophy, congenital myopathies, and Charcot-Marie-Tooth disease. These conditions can be caused by mutations in specific genes that affect the function of the nervous system or the muscles themselves.
It’s important to note that not all neuromuscular disorders are genetic. Some may be caused by factors such as autoimmune diseases, infections, or injuries to the nervous system or muscles. However, many neuromuscular disorders do have a known genetic cause, and understanding the genetic basis of these conditions is important for diagnosis and treatment.
Genetic Sequencing for Diagnosing Neuromuscular Disorders
Baylor Genetics’ Global Metabolomic Assisted Pathway Screening (Global MAPS®) is an innovative and comprehensive genetic test used to study metabolites, found in frozen plasma or urine samples. We developed this test with Metabolon, a global leader in metabolomics, to help your patients find the link between their disorder and metabolic pathways.
Introduced in 2014, Global MAPS® provides a comprehensive metabolic profile that can help identify differences in the metabolic pathway that are indicative of inborn errors of metabolism (IEM). For healthcare providers seeking to clarify a patient’s diagnosis, Global MAPS® is a unique clinical test that can also be utilized to assist with molecular interpretation for variants of uncertain significance (VUS). Additionally, Global MAPS® has tremendous potential to assist ill patients, including newborns and children by providing critical insights into the underlying metabolic dysfunctions and genetic factors contributing to an affected child or newborn’s condition. This enables healthcare providers to make more timely informed decisions regarding diagnosis, treatment, and care.
Overall, Global MAPS®, serves as a powerful tool for comprehending the fundamental origins of metabolic disorders in affected individuals of all ages. To ensure our healthcare providers have the information they need to see if Global MAPS® is an appropriate option for their patient, let’s take a closer look at how the test is performed at Baylor Genetics.
HOW DOES GLOBAL METABOLOMIC ASSISTED PATHWAY SCREENING WORK?
Once a healthcare provider has determined that Global MAPS® is the most suitable choice for their patient, the sample is sent to Baylor Genetics. Upon arrival, the sample undergoes metabolic screening using high-resolution mass spectrometry, a process that involves collaboration between Baylor Genetics and Metabolon.
After the screening, Baylor Genetics reviews the patient’s clinical history and the lab results for a final interpretation. The analytes we review include amino acids, organic acids, purines, and pyrimidines.5 Typically, over 700 analytes are detected in each sample.
The final, comprehensive patient report could include abnormal findings in a patient’s sample and the corresponding causes of metabolic deficiencies. Correlation with molecular findings can be performed to help clarify genetic variations affecting metabolic pathways. The identification of any rare or altered analytes within the biochemical pathway can contribute to expediting the diagnostic process. 2
“We continue to make diagnoses [for] not only well-known IEM disorders, but also collaborate with researchers, using Global MAPS® as an explorative tool, to uncover new biomarkers or disorders that have not yet been identified,” said Dr. Qin Sun, Senior Division Director of Clinical Genomics at Baylor Genetics.
Additionally, Global MAPS® can serve as a useful adjunct tool to Whole Exome Sequencing (WES) and Whole Genome Sequencing (WGS) by helping confirm variants and providing valuable functional data that may not otherwise be clinically available, resulting in improved variant classification.6
WHAT CAN GLOBAL METABOLOMIC ASSISTED PATHWAY SCREENING DETECT?
Global MAPS® detects shifts in biochemical pathways, that help us understand how disorders may develop. This technology enables us to diagnose conditions, help providers treat illnesses better, and provide molecular insights into the potential causes of disorders by detecting IEMs.
IEMs are inherited disorders that typically occur because of recessive variants in genes responsible for transmembrane transporters or for encoding metabolic enzymes.1 This test provides insight into the possible disorders that the patient may be experiencing, thought confirmation testing may be needed.
Global MAPS® can detect a wide range of IEMs including:
- Disorders of amino acid metabolism
- Organic acidemias
- Purine disorders
- Pyrimidine disorders
- Certain mitochondrial disorders
- Creatine disorders
- Bile acid disorders
- Urea cycle disorders
- Fatty acid oxidation disorders
- Neurotransmitter disorders
- Peroxisomal disorders
Note: A detailed disorder list can be found here.
WHEN IS GLOBAL METABOLOMIC ASSISTED PATHWAY SCREENING RECOMMENDED?
Global MAPS® is designed to find the answers previously left unresolved by other genetic tests. If your patient is experiencing complex clinical symptoms, or an undetermined phenotype, Global MAPS® may be the appropriate test.
Global MAPS® is recommended for patients who have:
- Autism spectrum disorder
- A VUS in a gene known to be involved in a small molecule (metabolite)
- Failure to thrive
- Seizures
- Hypotonia
- Hypoglycemia
- Recurrent vomiting
- An undifferentiated phenotype possibly related to an interruption in a biochemical pathway
WHAT TYPE OF RESULTS ARE RETURNED ON A GLOBAL METABOLOMIC ASSISTED PATHWAY TEST?
Global MAPS® yields four different results:
- Significantly altered analytes were detected and are possibly related to the patient’s phenotype.
- Rare analytes are present in the sample and are possibly related to the patient’s phenotype.
- Common analytes are absent in this sample and are possibly related to the patient’s phenotype.
- Significantly altered analytes were detected and are possibly related to nutrition, diet, supplements, or medication.
WHAT ARE THE BENEFITS OF GLOBAL METABOLOMIC ASSISTED PATHWAY SCREENING?
Global MAPS® is beneficial in paving the way for new research in the genetics industry.3 Other benefits of Global MAPS® include:
- A single screen to test for many IEMs
- Identification of molecules for which there is no other testing available, including:4
- Amino acids
- Organic acids
- Lipids
- A fast turnaround time of 3 weeks
- Promotion of research based on metabolic changes
- A useful tool for undiscovered phenotypes
WHAT ARE THE LIMITATIONS OF GLOBAL METABOLOMIC ASSISTED PATHWAY SCREENING?
Although Global MAPS® can identify many IEMs, there are a few limitations.
Global MAPS® cannot identify:
- Proteins or large peptides
- Complex oligosaccharides
- Large lipids
- Elements (e.g., K, Na, etc.)
“Global MAPS® is as a screening test,” said Carli Andrews, MS, CGC, Medical Science Liaison at Baylor Genetics. “Targeted biochemical testing and/or molecular testing may be indicated.”
Furthermore, Global MAPS® is not suitable for patients who are critically ill or on total parenteral nutrition.
WHAT GLOBAL METABOLOMIC ASSISTED PATHWAY SCREENING OPTIONS DOES BAYLOR GENETICS OFFER?
Baylor Genetics accepts two sample types for Global MAPS®:
- Global Metabolomic Assisted Pathway Screen Plasma (test code 4900)
- Global Metabolomic Assisted Pathway Screen Urine (test code 4901)
IS BAYLOR GENETICS’ GLOBAL METABOLOMIC ASSISTED PATHWAY SCREENING RIGHT FOR MY PATIENT?
Global MAPS® has helped usher in a new era of biochemical testing. This comprehensive screen requires only one sample from your patient for diagnosis, making the testing process quick and convenient. Furthermore, Global MAPS® can significantly benefit newborns and children by providing valuable insights into their metabolic and genetic profiles. By facilitating early detection, accurate diagnosis, personalized treatment approaches, and monitoring disease progression, Global MAPS® empowers healthcare providers with the knowledge needed to make informed decisions and deliver tailored care to these vulnerable patients.
For nearly a decade, Baylor Genetics has been identifying IEMs in patient’s metabolic pathways. We have the experience and knowledge you can rely on. Our goal is to serve our providers with a fast, comprehensive test that gives them the results needed to take the next steps in your patient’s healthcare journey.
Learn more about Global MAPS®.
To start a test order, visit: http://bit.ly/3nInw9b
References:
- Miller et. Al., Untargeted metabolomics analysis for the clinical screening of inborn errors of metabolism, Journal of inherited Metabolic Disease, 2015. Published online April 15.
- Atwal et. Aromatic I-amino acid decarboxylase deficiency diagnosed by clinical metabolomics profiling of plasma, Molecular Genetics and Metabolism, 2015, 115(2-3): 91-94
- Baylor Genetics. Global MAPS® 2023, February. https://www.baylorgenetics.com/global-maps/#:~:text=Using%20state%2Dof%2Dthe%2D,%2C%20urine%2C%20or%20cerebrospinal%20fluid.
- Baylor Genetics. Medical Genetics Test Details. (2023, February). https://www.bcm.edu/research/medical-genetics-labs/test_detail.cfm?testcode=4900&show=1&CFID=13687457&CFTOKEN=63927464
- National Center for Biotechnology Information. Global Metabolic Assisted Pathway Screen (Global MAPS®) 2023, February. https://www.ncbi.nlm.nih.gov/gtr/tests/571097/methodology/
- Alaimo JT, Glinton KE, Liu N, Xiao J, Yang Y, Reid Sutton V, Elsea SH. Integrated analysis of metabolomic profiling and exome data supplements sequence variant interpretation, classification, and diagnosis. Genet Med. 2020 Sep;22(9):1560-1566. doi: 10.1038/s41436-020-0827-0. Epub 2020 May 22. PMID: 32439973; PMCID: PMC7483344.
