Identifying gene variants of cystic fibrosis in Dominicans and Puerto Ricans.

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Cystic fibrosis (CF), a disease caused by a mutation in the CFTR gene, is known to primarily affect non-Hispanic White populations, but recent studies show CF incidence among other racial and ethnic groups. A test for CF that measures the level of chloride in sweat is currently the most reliable test for the disease. Another test, which detects CF gene variants, is used in newborn screenings to help guide early treatment. However, most known CF gene variants were identified in studies of White people; these gene variants are not necessarily relevant for racial and ethnic minority patients, who may experience delayed diagnosis and treatment of CF.

A study was conducted to describe the CF gene variants in 61 people in the Dominican Republic and 21 in Puerto Rico with clinically diagnosed CF. The participants were at least 6 years old and recruited from CF clinics, where their blood samples were drawn and sent to U.S. laboratories for gene sequencing and analysis.

The researchers found more than 1,500 variants in the CFTR gene among the 82 study participants. Based on databases and predictions about the gene, the researchers determined that only 30 of these variants have the potential to cause the disease. More than two-thirds of the Dominicans and 10% of the Puerto Ricans had none of the known CF gene variants—although they all had CF. Therefore, newborn screenings based on known CFTR variants would likely miss CF diagnoses in many Dominicans and Puerto Ricans who have the disease.

The research findings show the importance of including diverse patient populations in gene studies, to help make tests such as CF genetic screenings work for everyone. By determining the gene variants that cause CF in patients of many racial and ethnic backgrounds, future research can help bring effective treatment for all CF patients—as early as right after birth.

Citation:
Zeiger, A. M., McGarry, M. E., Mak, A. C. Y., Medina, V., Salazar, S., Eng, C., Liu, A. K., Oh, S. S., Nuckton, T. J., Jain, D., Blackwell, T. W., Kang, H. M., Abecasis, G., Oñate, L. C., Seibold, M. A., Burchard, E. G., & Rodriguez-Santana, J. (2020). Identification of CFTR variants in Latino patients with cystic fibrosis from the Dominican Republic and Puerto Rico. Pediatric Pulmonology, 55(2), 533–540. https://doi.org/10.1002/ppul.24549