DNA research disparities

Genetic screening for metabolic disorders is more accurate
for white than nonwhite newborns, a Stanford Medicine
study found. The researchers described the problem and suggested corrective steps in the December 2023 study in Genetics in Medicine. The study, they said, showed the need to update DNA databases to reflect disease-causing gene variants in nonwhite populations who have historically had less access to DNA testing.

Conventional tests for metabolic disorders in newborns measure biochemicals in blood or urine, providing clear-cut diagnoses without relying on genetic information. But DNA tests have gained prominence in the past decade in part because they can help families not only learn a baby’s diagnosis after birth but also get clues to the risk of disease during pregnancy.

To measure how well DNA tests discerned metabolic disease in nonwhite babies, the researchers compared the results of biochemical versus genetic screening of all infants referred to a metabolic genetic service over an 18-month period.

A total of 136 infants were referred based on results from a first-step biochemical screen of blood from a heel prick. Nineteen of them were diagnosed with metabolic diseases based on follow-up biochemical testing. Of those, 18 also underwent genetic testing. Ten of them had an ambiguous result: at least one variant of uncertain significance, a genetic change for which disease risk was not known. Of those 10, nine were of nonwhite ancestry.

“The reality is if you don’t test people of nonwhite ancestry, it’s this futile cycle: The lab’s databases never diversify either,” said the study’s senior author, Christina Tise, MD, PhD, assistant professor of pediatrics.

Read the full story here.