To examine the effects of CFTR genotype, we divided the CF group into two subgroups: the first included heterozygous DF508 and other genotypes (n = 24), because only three of the CF group did not have at least one DF508 allele, and the second group comprised individuals homozygous for DF508 (n = 18). The gene discussed is CFTR; the disease is cystic fibrosis.