Molecular
& genetic basis of Cystic Fibrosis
The CF Protein creates a Cl--permeable
channel in the outer cell membrane. Persons with Cystic Fibrosis (OMIM219700)
are typically homozygous for an allele with a 3bp deletion (508 allele)
that removes a Phenylalanine residue from a position near a
nucleotide-binding domain. CF
proteins with this defect are destroyed by the cell, and
in the absence of Cl--channels, the Cl- / Na+ balance of the
cell is disrupted. This leads to an accumulation of mucous in the
lungs, a condition that is ultimately fatal.