Salivary Electrolyte Concentrations Are Associated with Cystic Fibrosis Transmembrane Regulator Genotypes

It is estimated that about one in 24 Belgian Caucasians is a cystic fibrosis (CF) heterozygote. Until now, CF heterozygotes can only be identified by genetic decoding (e.g. Inno-Lipa CF2 test), as they cannot be phenotypically distinguished from the general population. The aim of this study was to evaluate differences in salivary electrolyte concentrations (calcium, bicarbonate, chloride, potassium, sodium and phosphate) and salivary osmolarity between CF homozygotes (n=41), CF heterozygotes (n=56) and healthy controls (n=65). Differences between the three groups were investigated by means of non-parametric tests. Several significant differences between the three study groups and among, as well as between, the different cystic fibrosis transmembrane regulator (CFTR) genotypes were observed. Significant differences in salivary electrolyte concentrations between individuals with delta F508 mutation and those without, and between CF homozygotes and heterozygotes were observed. The concentrations of several salivary electrolytes, and salivary osmolarity were significantly higher in CFTR genotype individuals. Differences in salivary electrolyte concentrations may partly explain differences in caries between the three study groups.