My son has the m470v, which is not considered to disease causing. They have not found his mutations, but had a positive sweat test. He has tons of gi symptoms with the need for a g tube and recently been experiencing bouts of DIOS. Gaining weight gas been a huge issue.
lung wise he has had spontaneous pneumothorax's and with falling pft's the last 3 visits he is going to start Tobi. Overall I think he has done well and the preventative treatments are key.
but let me stress we have been told this polymorphism is not considered to be contributing to any of his symptoms.
I hope this helps.