North Texas Researchers Find A New Screening Process For Rare Genetic Diseases
Researchers at UT Southwestern Medical Center and Children’s Health have developed a new screening approach that can more quickly identify diseases hard to diagnose in kids.
About 25% of admissions at pediatric hospitals result from genetic and metabolic diseases difficult to diagnose and treat effectively.
Dr. Ralph Deberardinis, a professor at the Children’s Research Institute at UT Southwestern, explains the new screening approach and why it's such a game changer.
The genetic diseases fall into two classes: There's "a class where mutation in the gene affects the way the body develops. Congenital heart defects would be an example of that. Then there are diseases that affect metabolism that are called in-born errors of metabolism, or IEM."
Why the diseases are hard to diagnose: "Their symptoms are often non-specific. The most common symptoms would be learning disabilities, or problems with the way the child grows. On top of that would be problems with the way the body controls its glucose levels. Some of these patients will become hypoglycemic or their blood will become more acidotic than it should be. But because metabolism is so complicated, it’s difficult for a doctor, even an expert, to look at a child with one of these diseases and immediately know what gene is mutated.
Current screening process: "Every baby in Texas is tested for about 30 different conditions, many of them genetic metabolic diseases, because they’re treatable. Implementing the treatment before the child becomes symptomatic with the disease, the outcomes are much better."
The rest of the diseases: "They have to be picked up by the doctor after the child becomes sick. The diseases often become harder to treat because there’s already been some damage to the brain, to the liver or to one of the other organs. The diagnostic voyage you have to take to pinpoint the problem can be quite long. It can take years in some cases."
New screening process: “We take a couple of drops of blood, spin out the cells in the blood to get the plasma, and then do a brief chemical extraction on the plasma to pull chemical compounds of interest in our case. We then inject that into a mass spectrometer and accurately measure the weight of every chemical compound found in the blood. We get a list of usually 5,000 chemical features and from that, we can usually derive a thousand unique chemical compounds."
Why metabolomics is a game changer: "Metabolomics gives you a second dimension of the analysis. Right now, I have a chemical makeup of the blood and all the genetic differences between my patient and the rest of the population. We can integrate those pieces of information to identify the mutations that are causing the chemical changes that are causing the disease."
For family members: "After pinpointing the gene, you can then go out in the extended family and figure out who else (besides mother and father) is carrying the mutation in that gene. This can be useful for risk counseling."