Identification of the 5T-12TG allele of the cystic fibrosis transmembrane conductance regulator gene in hypertrypsinaemic newborns

In order to increase knowledge of the pathogenic effect of the 5T-12TG allele of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, we evaluated its presence in 24 hypertrypsinaemic newborns with borderline sweat tests. Among 20 CFTR-identified alterations, the 5T-12TG haplotype was the second most frequent mutation (14.6%) over F508del. Conclusion: Our study suggests the need for searching for this allele in hypertrypsinaemic infants with inconclusive sweat tests.