Table 1. Single nucleotide polymorphism (SNP) information.

SNP ID	Alleles	Peptide shift	Synonymous change	Peptide location (aa)
rs2305619	A/G
rs3816527	C/A	Ala → Asp	No	48
rs1840680	A/G
rs3845978	C/T
rs35948036	C/T	None (Leu)	Yes	16

Abbreviations: Ala, alanine; Asp, aspartic acid; Leu, leucine.

We examined 127 (70 females, 57 males, age range, 11–52 years) Caucasian patients homozygous for the F508del mutation, who were followed up at the Regional Cystic Fibrosis centre of Verona (Italy). The study protocol was approved by Verona Azienda Ospedaliera and Brescia Spedali Civili Ethics Committees. Patients and parents of minors provided written informed consent. Clinical, biological and functional data were obtained retrospectively from patients' hospital records.

To validate allelic frequencies of SNPs in our population, we have collected cord blood samples from a total of 165 children (72 females, 93 males) from the Department of Obstetrics at Spedali Civili of Brescia.