A frame-shift mutation in the cystic fibrosis gene.
Cystic fibrosis (CF) is a common recessive lethal genetic disorder, affecting 1 in 1,600 Caucasians. The disease causes defective regulation of chloride-ion transport in exocrine cells. Although in all CF families the disease is linked to a locus on chromosome 7q31, there is clinical heterogeneity in the severity of the disease and the age at which it is diagnosed. CF is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. A three-nucleotide deletion (delta F508) causing the loss of a phenylalanine residue in the tenth exon of the CFTR gene has been found on 70% of CF chromosomes. We have now characterized a CF family in which neither parent of the affected individual carries the common mutation, and identified a two-nucleotide insertion in the CF allele of the mother. The mutation introduces a termination codon in exon 13 of the CFTR gene at residue 821, and is predicted to result in the production of a severely truncated nonfunctional protein.
Laboratory of Viral Carcinogenesis, National Cancer Institute, Frederick, Maryland 21701.
M B
MB
White
J
J
Amos
J M
JM
Hsu
B
B
Gerrard
P
P
Finn
M
M
Dean
D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D002897:Chromosomes, Human, Pair 7; D003550:Cystic Fibrosis / Q000235:genetics*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D006579:Heterozygote; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D016133:Polymerase Chain Reaction
C505032:CFTR protein, human; D008565:Membrane Proteins; D019005:Cystic Fibrosis Transmembrane Conductance Regulator