In analyzing the metabolic profiles of healthy American children, researchers found surprising differences between ethnic groups, possibly based on cultural factors such as diet and language. These findings may eventually help make screening for inherited metabolic disorders, cystic fibrosis or hypothyroidism more accurate than screening for traditional genetic diseases, which in some cases lead to false positives.
“We don’t want to lose a child who could potentially be sick, and we don’t want to put families through the burdens and fears that can result from a false positive test,” Kurt Scharfassociate professor of genetics at Yale University School of Medicine and senior author of the study published in the journal Molecular Genetics and Metabolism.
For the study, Scharfe and colleagues analyzed data collected from more than 400,000 children, representing 17 self-reported ethnic groups, who were part of a California newborn screening program. Specifically, they wanted to see if these ethnic differences could be detected in metabolites, the molecules that provide energy by breaking down food or body tissues such as fats in children’s blood.
The question was not only of academic importance, but of concern to pediatricians. For example, it is known that children of African descent are more likely to have elevated blood biomarkers indicative of cystic fibrosis than children born to white parents, although children born to white parents are more likely to eventually develop the disease. The researchers hope that using ratios to explain these differences in marker levels may provide more accurate ways to assess risk than traditional genetic testing.
It is also known that people of African heritage have greater genetic diversity than those of other ethnic groups because they descend from the world’s oldest ancestral population. Modern humans migrated from Africa to regions across the planet; Other ethnic groups are descendants of these original immigrants, and they have enough diversity in their DNA to make them genetically identifiable.
But the researchers found that metabolic strains can tell a different story. For example, while there is a clear demarcation between genetic variants between African Americans and European Americans, researchers have found that these two groups are metabolically more closely related. Conversely, while people of Japanese and Chinese ancestry, for example, are genetically closely related, researchers have found greater differences in their metabolic profiles.
“This testifies to the role of the environment in shaping our metabolism,” Scharf said. “Where people share the same culture and food [as many Black and white Americans have for generations], The metabolic features are more similar. When people are separated by circumstances, such as language or lifestyles, the differences in metabolism are greater than the genetic differences.”
Scharfe cautions that more work needs to be done before the results can be applied clinically. The researchers analyzed only 41 out of several hundred metabolites and relied on parents’ reports of their ethnic heritage, which may not always correspond to reality.
“This is just a preliminary snapshot, but understanding our metabolic ancestors has a promising future.
Gang Peng, a research associate in biostatistics and bioinformatics in the Departments of Biostatistics and Genetics at Yale University, is the study’s first author.