Buccal cell DNA analysis in premature and term neonates: screening for mutations of the complete coding region for the cystic fibrosis transmembrane conductance regulator.

Abstract

Traditionally, cystic fibrosis (CF) is diagnosed either by measuring sweat electrolyte levels or by screening for mutations using genomic DNA isolated from leucocytes. The aim of this work was to develop a modified fast and non-invasive tool for the collection of cell samples and the genetic analysis of the entire coding region for the cystic fibrosis transmembrane conductance regulator (CFTR) in newborns, especially premature infants. Cell samples were taken by scraping the buccal mucus with tiny dental brushes, followed by DNA isolation and mutation analysis using SSCP-heteroduplex (single-strand conformation polymorphism) screening and sequencing. We have demonstrated that buccal cell DNA collected from premature and term newborns yields sufficient DNA (at least 60 ng) to perform a mutation screening of the complete CFTR coding region, independently of the patients' weight (mean 2200 g) or gestational age (mean 35 weeks). The high stability of the samples at room temperature admits the possibility of dry shipment of samples collected elsewhere to the diagnostic laboratory. This fast, non-invasive sampling and DNA isolation method allows for early diagnosis of CF, initiation of therapy and minimisation of parental uncertainty and offers a technique for mutation analysis in any other monogenic disorder.