Q493X

Question

My daughter has just had Q493 identified as her second mutation. (She also has D508)
Can you tell me anything about Q493 as it seems fairly rare?

Answer

Thank you very much for your question. The Q493X is a class I mutation, F508del is a class II mutation. Indeed Q493X is a rare mutation, whilst F508del is a common mutation. The prognosis for this combination of mutations is not known, however, is likely to follow a similar pattern to those who have 2 copies of F508del. This is usually associated with a combination of lung disease and pancreatic insufficiency. It is important to note, however, that making a prognosis based only on genotype is very difficult. People with the same two copies of the mutated CFTR gene may experience very different symptoms.

Stop mutations such as Q493X may be helped by a new drug PTC-124 (Ataluren). This is currently in a pivotal trial.

Best wishes
Stuart Elborn
Lisa Kent

17.12.2010

The answer is edited by: Prof Stuart Elborn