Cystic Fibrosis (CF) is the most common life-threatening genetic disease and is a progressive, permanent disorder in which the glands making sweat, mucus and intestinal secretions don’t function correctly. Clinical Symptoms
The accumulation of thick, sticky mucus associated with CF, blocks the tubes that transport air resulting in lung and sinus infections, wheezing and persistent coughs. Thick mucus can obstruct tubes that transport digestive enzymes from the pancreas to the intestine leading to an inability to absorb the nutrients in food. The result is poor weight-gain/growth, foul-smelling stools and intestinal blockage. Male sterility and reduced fertility in females can occur. Causative Mutations
CF is caused by a mutation in the gene “cystic fibrosis transmembrane conductance regulator” (CFTR) on chromosome seven. 70% of all mutations in the gene involve the deletion of 3 nucleotides resulting in loosing the amino acid phenylalanine in position 508 , naming this mutation ∆F508. There are over 1500 other mutations, however, that can produce CF. Most people have 2 functioning allele of the CFTR gene and CF develops when both are faulty. Consequences of mutation at cellular and physiological level The usual allele for this gene codes for a membrane protein that’s function is transportation of chloride ions between certain cells and the extracellular fluid. In mutation ∆F508, the proteins with deleted phenylalanine don’t insert into the membrane resulting in ion migration of chlorine being disrupted leading to the build-up of mucus. Chlorine’s negative charge disrupts the electrical potential of the cell causing certain molecules i.e. sodium to enter. The combination of NaCl is then excreted in vast amounts. This alters the balance of ions in the blood leading to abnormal heart rhythms. Treatment
CF is incurable. However, daily doses of antibiotics help to prevent infection, vitamin supplements aid the absorption of nutrients, gentle...
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