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- Question
- Hello, I am carrying the mutation F508 and my spouse th mutation 3849 + 10kbc> T. Is it possible to know how many people have the F508 / 3849 + 10Kbc> T in the French register? And have the newborns F508 / 3849 + 10Kbc> T been tested for Guthrie? What are their symptoms? Thank you for your help. Best regards
- Answer
- Hello,
The data concerning the patients registered in the French Register of Cystic Fibrosis (CF) are not accessible to online requests that would allow to answer the questions you ask in particular the number of patients carrying in France a genotype F508del / 3849 + 10Kbc> T and the proportion of patients diagnosed following systematic neonatal screening for cystic fibrosis.
I have sent a request to the French CF Register. Waiting for the answer, I am sending you information from the CFTR2 site held by Johns Hopkins Hospital, Baltimore, ML, USA. This online accessible site harnesses data from nearly 100,000 individuals with CF worldwide. Comparison of the data from 645 patients with the F508del / 3849 + 10Kbc> T genotype with those of the 53,309 patients who had 2 mutations in the CFTR gene, one of which at least F508del showed that:
- Pancreatic insufficiency is present in only 245 of the 645 patients F508del / 3849 + 10Kbc> T (35%) whereas it is present in 88% of the 53,309 patients in the other group;
- the average concentration of sweat chloride is 66 mmol/l versus 96mmol/l in the other group.
This difference is explained by the fact that the mutation 3849 + 10Kbc> T is a class V mutation which allows the synthesis and migration in the cell membrane of an amount of functional CFTR (or chlorine channel) protein.
Data from databases, however, should be interpreted with caution because even though they have an undeniable statistical value, they cannot predict the course of the disease in a given patient. The evolution of the disease is indeed peculiar to each patient because it can be influenced by environmental factors (lifestyle, atmospheric pollution ...) and genetic factors other than the CFTR genotype, notably so-called modifying genes which are a search object.
Hope this answer can help.
Best wishes
Gilles RAULT, MD, Roscoff CF Center
- 14.02.2017
