Cftr gene

CFTR is the acronym for "Cystic Fibrosis Transmembrane Conductance Regulator". The gene is located on chromosome 7 in the region of band q31.3. The CRTF protein is a protein fixed on the surface of cells, a so-called chloride channel, which occurs mainly in the cell membrane of epithelial cells. Mutations in the CFTR gene cause absence or dysfunction of the channel in humans.

Cystic fibrosis (CF): In more than 70% of affected individuals in Central Europe, the mutation Delta F508 is found, which leads to the deletion of a phenylalanine at amino acid position 508 of the CFTR protein .

To date, a total of over 1000 different mutations in the CFTR gene have been described, although not all of them cause cystic fibrosis. More than 360 gene mutations have been identified that cause association with CF, although most are extremely rare. People with CF can have either two copies of the CFTR gene with the same mutation (homozygous) or two copies with different mutations (heterozygous).

The five most common CFTR gene mutations worldwide are:

• F508del
• G542X
• G551D
• N1303K and
• R117H.2

Mutations in the CFTR gene in humans result in the absence or impaired function of the duct, which is the cause of cystic fibrosis and congenital aplasia of the vas deferens (CAVD). Furthermore, chronic pancreatitis may be associated with CFTR mutations.

Cystic fibrosis: F508del is the most common mutation of the CFTR gene: It is estimated that approximately two-thirds of all CFTR gene mutations worldwide are F508del mutations. The next most common mutations - G542X, G551D, N1303K and R117H - each have a frequency of only 1-2.5% worldwide.

Hereditary pancreatitis: In the case of isolated chronic pancreatitis, the mutations often differ from the disease-causing mutations of cystic fibrosis. Paradoxically, patients carrying a mild cystic fibrosis genotype have an increased risk of developing pancreatitis at a given time compared to patients carrying a moderate-severe genotype (Ooi CY et al. 2010). This observation suggests that CF patients with more residual CFTR function are at higher risk for pancreatitis (Ooi CY et al. 2010).

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