The most common mutation causing CF is a deletion of F508 Wh

The most common mutation causing CF is a deletion of F508. What are the cellular consequences of the F508 deletion?

Solution

The deletion of F508 is the most common mutation. It is a deletion of 3 nucleotides spanning positions 507 and 508 (deletion of the C-G pair) of the CFTR gene located on chromosome 7. These deletion leads to loss of single codon which codes for amino acid phenylalanine (F). A person with this CFTRF508 mutation will produce abnormal CFTR protein which lacks the phenylalanine residue, as a result is cannot fold properly. This abnormal protein cannot escape the endoplasmic reticulum for further processing.

Normal CFTR protein is a transmembrane protein which opens channels and releases chloride ions out of the cells. Deletion of F508 lead to abnormal protein which degrades and hence ion transport is not performed.