# CFTR Variant Frequencies and Newborn Screening Panel Performance in the Diverse CF Population Receiving Care in the State of Georgia

## TL;DR

This study evaluates how well current and expanded newborn screening panels detect cystic fibrosis in Georgia's diverse population, aiming to improve early diagnosis and reduce disparities.

## Contribution

The study introduces findings on the performance of expanded CFTR variant panels in a diverse population and highlights equity gaps in diagnosis.

## Key findings

- An expanded panel with 719 CFTR variants improves case detection from 93% to 97%.
- Detection rates for non-Hispanic Black individuals remain lower than for non-Hispanic White individuals even with expanded panels.

## Abstract

Cystic fibrosis (CF) newborn screening (NBS) aims to improve outcomes through early diagnosis, yet disparities in time to diagnosis remain. This study examines CFTR allele frequencies and variant panel performance among a diverse CF population in Georgia to inform recommendations for updating the NBS algorithm and improving equity. This cross-sectional study includes 969 people with CF (PwCF) from Georgia’s accredited CF centers. CFTR variant frequencies were calculated according to race and ethnicity. Panel performance was evaluated for Georgia’s current Luminex-39 variant test and three expanded panels. Statistical analyses compared detection rates across panels and demographic groups. Georgia’s diverse CF population demonstrates a unique CFTR allelic variability compared to national data. Increasing panel size enhances case identification. A panel including 719 CF-causing variants from the CFTR2 database significantly improves case detection from 93% to 97% (p = 0.002), as well as two-variant detection from 69% to 86% (p < 0.001). Detection of minoritized PwCF also improves with increasing panel size. However, even using the 719-variant panel, detection of non-Hispanic Black PwCF remains significantly lower compared to non-Hispanic White PwCF (case detection: p = 0.003; two-variant detection: p < 0.001). In conclusion, the use of expanded CFTR panels for NBS in Georgia would enhance timely diagnosis and improve equity.