Abstract
More than 1000 mutations have been identified in the cystic fibrosis (CF) transmembrane regulator (CFTR) disease gene. The impact of these mutations on the protein and the wide spectrum of CF phenotypes prompted a series of genotype-phenotype correlation studies. The CFTR genotype is invariably correlated with pancreatic status in about 85% of cases with pancreatic insufficiency and in about 15% of cases with pancreatic sufficiency. The correlations between the CFTR genotype and pulmonary, liver, and gastrointestinal expression are debatable. The discordant phenotype observed in CF siblings, as in our patient Mary, argue against a major role of environmental factors and suggest that the genes other than CFTR modulate the CF phenotype. Although the identification of modifier genes could improve the quality of life, nutritional status may also contribute to the lowering of morbidity and mortality of CF patients.