Newborn babies with cystic fibrosis who are from non-White ancestry are more likely to be left undiagnosed by healthcare staff, according to research from the University of California.
The inherited disorder cystic fibrosis, which causes lung and other organ damage due to excessively thick and sticky mucus, is more common in non-Hispanic White populations of European ancestry, but can occur in any population group and about 20% of those with the condition come from a non-White background. It is a complex disorder and can be caused by almost 2000 different mutations in the CFTR gene.
Early diagnosis is important. While there is still no cure, treatments have improved enormously and early interventions and treatment can reduce organ damage, improve quality of life and significantly extend the lifespan of these children.
For more than 10 years, cystic fibrosis screening of newborns has been in place across the U.S. The panels and the mutations screened for tend to include the most common CFTR mutation, F508del, which accounts for up to 70% of cases and sometimes a panel including a few other possible variants.
Unfortunately, this means that children with rarer, or less well-known mutations are at risk of being given a false negative diagnosis, only to return to hospital with serious symptoms at a later date.
Disease-related genetic variants can vary considerably across populations. Many genetic studies and biobanks have a large number of participants of White, European origin, which has led to diagnostic problems in people of other ethnicities who may carry disease-related variants that are uncommon, or not seen, in White populations.
In this study, recently published in Pediatric Pulmonology, Meghan McGarry, associate professor of pediatrics at UC San Francisco Benioff Children’s Hospitals, and colleagues used data from the CF Foundation Patient Registry to assess rates of delayed diagnosis in individuals with the condition.
They found that at least one CFTR genetic variant was detected on newborn screening in 87% or more non-Hispanic White people with cystic fibrosis, but this detection was as low as 42% in Black, Asian and Hispanic people with the condition.
Across the 46,729 people genotyped in the CF Foundation Patient Registry, 3.8% had a false negative newborn screen and 11.8% had a delayed diagnosis. People in the registry who were not of non-Hispanic White background had higher rates of false negatives and delayed diagnosis compared with those in this group.
“Newborn screenings are meant to be a public health measure that is equal across populations, but in practice, we are actually creating disparities because children of color are going undiagnosed for cystic fibrosis until an older age,” said McGarry, in a press statement. “That means they are treated later when symptoms occur, and their outcomes are often worse.”
McGarry advocates for more diverse genetic panels to be used for this type of screening to make sure as many cases are picked up early as possible.
She added: “Three states—Wisconsin, New York and California—do this well and use full sequencing, as well as systematically monitor and review who is being missed, what variants they had, and whether they should be adding variants to the panels.”