CYSTIC-FIBROSIS SCREENING IN NEONATES - MEASUREMENT OF IMMUNOREACTIVETRYPSIN AND DIRECT GENOTYPE ANALYSIS FOR DELTA-F508 MUTATION

This study investigated the clinical usefulness of screening for cysti c fibrosis (CF),in 19 992 newborns, over 39 months, in an Austrian pop ulation. Immunoreactive serum trypsin (IRT) determination was followed by sweat chloride analysis (sweat test) to establish diagnosis. In a retrospective analysis covering 6 months of the study period, individu als who were considered to be at risk after IRT estimation (n = 22) we re analysed for Delta F508 mutation, using a new method of DNA extract ion from the initial dried blood specimens. A total of 119 infants (0. 6%) had values greater than 750 ng trypsin/ml whole blood. In 88 babie s sweat tests were performed, leading to the diagnosis of CF in 11 cas es. One patient was not initially identified by screening but was late r discovered due to his clinical status. Three infants were noted to c arry the Delta F508 mutation (1 homozygous, 2 heterozygous). Two of th ese babies already had CE The second heterozygote was a carrier. A hig hly efficient three tier screening strategy is presented in which IRT estimation, determination of Delta F508 status and sweat chloride test ing could lead to a high sensitivity analysis of this population.