Cystic fibrosis (CF) occurs less frequently in nonwhites than in whites, and nonwhites tend to be diagnosed at a later age. This late diagnosis often comes only once they have become symptomatic, rather than through newborn screening programs or molecular diagnostic testing. Delaying diagnosis can result in postponed treatment and clinical deterioration.

A new study in The Journal of Molecular Diagnostics found that one reason for this ethnic disparity in CF diagnoses is that the variants examined in the most common CF newborn screening panels do not sufficiently include the variants present in nonwhite populations.

The researchers found that 90% of white patients and 83% of Native Americans with CF have a particular mutation (p.Phe508del), and about half of these individuals have two copies of these mutations. However, they found that 30% of Hispanics, 38% of blacks, and 41% of Asians did not even have one copy of the mutation. Patients of Hispanic, black, or Asian ancestry were also less likely to have two identified CFTR variants.