Cystic fibrosis

Cystic Fibrosis

Cystic Fibrosis is an autosomal recessive disease located on chromosome 7. Cystic Fibrosis is caused by a mutation to the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) channel. The most common mutation is ΔF508, accounting for 70% of mutations in the Caucasin UK population, in which the triplet code (codon) for the amino acid phenylalanine is deleted, disrupting Cl^- transport. This mutation belongs to the Class II group of mutations causing Cystic Fibrosis.

CFTR is composed of 3 types of domains. There are 12 Transmembrane spanning domains, 2 Nucleotide Binding Domains (NBD’s) and an R domain (regulatory domain). The NBD’s are involved in the binding and hydrolysis of ATP.

Cystic Fibrosis can be divided in to five classes:

Class I: Premature Stop Codons (e.g. W1282X)

Class II: Abnormal Processing (e.g. ΔF508)

Class III: Altered Regulation (e.g. G551D)

Class IV: Conductance Defect (e.g. R117H)

Class V: Reduced Protein Synthesis (e.g. A455E)