Why Cystic Fibrosis Newborn Screenings May Miss Babies In Some Demographics

Cystic fibrosis is a rare genetic disease that causes a gene mutation affecting the cystic fibrosis transmembrane conductance regulator (CFTR) gene (via Cystic Fibrosis Foundation). When the CFTR gene is mutated, it causes the CFTR protein to malfunction, which makes the mucus in various organs become thick and syrupy as opposed to thin and slippery (per Mayo Clinic). This in turn impacts the lungs, pancreas, and various other organs.

Roughly 40,000 American adults and children are living with cystic fibrosis, according to the Cystic Fibrosis Foundation. While people can be diagnosed with this disorder at any age, many people are diagnosed early on because of cystic fibrosis newborn screenings.

While newborn screenings are a multistep process, new research published in the journal Pediatric Pulmonology is showing that these newborn screenings may miss babies in some demographics. Lead study author Dr. Meghan McGarry explains to U.S. News & World Report that "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." This delay may then create worse results later on. For instance, Dr. McGarry comments that the outcomes are often much worse when cystic fibrosis is treated once symptoms start surfacing. Early detection may help reduce these symptoms and help patients better manage their cystic fibrosis early on.

During the study, researchers examined the CFTR variants in 46,729 patients using the Cystic Fibrosis Foundation Patient Registry from 2020 (via Pediatric Pulmonology). Using these genetic panels, the researchers looked for differences in detection rates, delayed diagnoses, and false-negative screenings by ethnicity and race. They then compared the results across each U.S. state, since genetic panels offered can differ by state, points out U.S. News & World Report.

What they found is that white patients had the highest detection rates for at least one CFTR variant, between 87.5% to 97% (per Pediatric Pulmonology). The lowest detection rates were found in Asian patients (41.9% to 77.4%), Black patients (53.7% to 86.1%), American Indian/Alaska Native patients (63.9% to 91%) and Hispanic patients (66.1% to 93.1%). However, when the researchers looked for two CFTR variants, the racial and ethnic gap grew. 

The study results noted that tests examining more variants had higher rates of detection, though not across the board for all races and ethnicities, which highlights the necessity of offering panels that better address more races and ethnicities. "In order for newborn screenings to be equitable, they must include CFTR variant panels that reflect the racial and ethnic diversity of the population," said Dr. McGarry to U.S. News & World Report. This will help lead to better outcomes later on, as permanent lung damage from cystic fibrosis can be seen as early as four weeks of age, Dr. McGarry said.