Advice about diagnosis please


New member
My 9 year old son is a carrier of F508del. We recently discovered this while trying to find out why he has had chronic diarrhea since the age of 2 years. He has never had any other symptoms of CF.
In the last 2 months we have been following strictly the Low-FODMAP diet and have managed to stop his chronic diarrhea if we follow it 100%. We did a full exome sequencing to identify a second mutation, but none were identified. We tested also my husband and I for CF mutations and found my husband to be a carrier also of F508del, and nothing for me.
The doctor says that to rule out CF and completely, we need to do deletion duplication of the CF gene but I don't understand what that means.
I'm wondering if you could advise me:
- could the digestive problems be due to carrier status of F508del? Is there a way we can confirm this?
- the only other sign of CF is that he has early aqueous wrinkling, which I've read can be linked to F508del. Would anyone suggest us doing the deletion duplication and what does this mean in layman's terms?
Thank you for any thoughts


Active member
F508 del is a mutation that leads to digestive issues. Your son should be seen at an Approved Cystic Fibrosis Clinic and diagnosed by a CF Specialist. Delta F508 leads to pancreatic insufficiency, which means that the pancreas is not producing enough enzyme to properly digest food, which caused chronic diarrhea. This is a RED FLAG for CF also.

I would suggest a FULL CF SEQUENCING.

Good luck,


New member
Thank you Bill.
We did a full/whole exome sequencing and they only found the heterogzyte F508del mutation.
The CF sequencing for me revealed nothing, for my husband it revealed the same heterogzyte F508del.
Can I conclude now that my son is only carrier of F508del?
If yes, can I conclude that being a carrier is sufficient to have pancreatic insufficiency?
The genetics company (Centogene) is telling us that the only way of being 100% sure that there is no other CF mutation is to do deletion/duplication. I don't know what this means. Do you?
Thank you


Staff member
It could be it's a yet to be identified CF mutation. Hopefully you'll be able to find a proactive doctor who will treat the symptoms, treat it as if it is CF. I know there are a couple individuals on this site who have similar issues. I believe some have gone thru nasal differential testing.


Super Moderator
Let me try a practical approach here. I would ask a CF Center or a gastroenterologist familiar with CF - perhaps a trial with enzymes would also relieve the diarrhea, whether they find a second gene or not! It may be so much simpler than a strict diet. So many new mutations are being found. As a Mom I want to know what will relieve my child's symptoms whether they can label it or not.


Active member
It means that your son needs a deletion/duplication scan. Yes he could be PI based upon a single mutation of Delta F508.



New member
The Cystic Fibrosis CFTR Gene Deletion or Duplication assay detects deletions and duplications within the promoter region and all 27 exons of the CFTR gene. Recent studies suggest that such rearrangements may account for 16% to 24% of mutant CFTR alleles not identified after extensive sequencing.[SUP] [/SUP]Because of the shorter turnaround time of the CFTR deletion/duplication test, clinicians may prefer to request it first and order extensive sequencing only if the result is negative.

Individuals Suitable for Testing

  • Individuals with symptoms of classic or atypical CF who have <2 CFTR mutations detected with standard mutation screening
  • Individuals with a family history of a large deletion or duplication in the CFTR gene
  • Family members of individuals with CF whose mutations are unknown