Newborn Screening for Cystic Fibrosis in California

Area of Science:

• Genetics and Genomics
• Public Health
• Pediatrics

Background:

• Newborn screening programs are crucial for early detection of genetic disorders.
• Cystic Fibrosis (CF) is a serious genetic disorder requiring timely diagnosis and management.
• California implemented a newborn screening program for CF to improve early identification.

Purpose of the Study:

• To evaluate the methods and performance of California's newborn screening program for Cystic Fibrosis (CF) over its first five years.
• To assess the effectiveness of a three-step screening model in identifying CF cases.
• To report on the prevalence and mutation spectrum of CF in a diverse newborn population.

Main Methods:

• A three-step screening process was employed for 2,573,293 newborns from July 2007 to June 2012.
• Step 1: Immunoreactive trypsinogen (IRT) measurement in dried blood spots.
• Step 2: Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) mutation analysis for elevated IRT levels.
• Step 3: DNA sequencing for specimens with one identified CFTR mutation.

Main Results:

• The program detected 345 CF cases, 533 CFTR-related metabolic syndrome cases, and 1617 carriers.
• CF prevalence was 1 in 6899 births, with 28 missed CF cases.
• Program sensitivity was 92% and positive predictive value was 34%, identifying 78 novel CFTR variants.

Conclusions:

• The implemented three-step newborn screening model demonstrated high detection rates for CF in a diverse population.
• The program achieved low false-positive rates, facilitating efficient diagnostic evaluations.
• Early identification through this screening approach supports timely intervention for infants with CF.