To the Editor: In a recent article Hamosh and Corey of the Cystic Fibrosis Genotype-Phenotype Consortium (Oct. 28 issue)1 reported on correlations between the genotypes and phenotypes of patients with cystic fibrosis. The mean age of the patients with the R117H/ΔF508 genotype was 23.5 years, and the ages of the other groups ranged from 11.0 to 14.6 years. The authors conclude that genotype is predictive of pancreatic status but not of the severity of pulmonary disease. In our adult patient population, however, we found a correlation between the genotype and the severity of pulmonary disease. The rate of decline.