Heterogeneity of phenotype in two cystic fibrosis patients homozygous for the CFTR exon 11 mutation G551D.

In the heterozygous state, the cystic fibrosis transmembrane conductance regulator (CFTR) exon 11 mutation G551D has been described as "severe," causing pancreatic insufficiency. Two cystic fibrosis (CF) patients homozygous for this mutation showed a mild rather than severe pancreatic phenotype and a variable pulmonary phenotype.