Cystic-fibrosis screening in the newborn

Area of Science:

• Biochemistry
• Neonatal screening
• Genetic disorders

Background:

• Cystic Fibrosis (C.F.) is a genetic disorder affecting multiple organs.
• Early detection of C.F. is crucial for timely intervention and improved outcomes.
• Current diagnostic methods can be invasive or time-consuming for newborns.

Purpose of the Study:

• To introduce and evaluate a novel colorimetric assay for detecting trypsin deficiency in newborns, indicative of C.F.
• To assess the sensitivity and specificity of this new method in a neonatal screening setting.
• To establish the efficacy of the assay in identifying infants with cystic fibrosis.

Main Methods:

• A colorimetric assay utilizing benzoyl-arginine-p-nitroanilide (B.A.P.N.A.) as a substrate.
• Measurement of p-nitroaniline release, which is dependent on trypsin activity.
• Analysis of stool samples from newborn infants for trypsin levels.

Main Results:

• The assay showed negligible color development in samples from infants with C.F. due to trypsin deficiency.
• 2 cases of C.F. were identified among 2500 screened newborns.
• False-positive rates were reduced to 0.05% after a second specimen and further refined to 0.1% after initial testing.
• No false-negative results were observed in older patients with untreated C.F.

Conclusions:

• The developed colorimetric trypsin assay is a sensitive and specific method for newborn screening of cystic fibrosis.
• The assay demonstrates a low false-positive rate, making it suitable for large-scale neonatal screening.
• This method offers a promising approach for early and accurate diagnosis of cystic fibrosis in infants.