What is the best CF genetic test?

[sanfloraine]

I was on this forum a few years ago, my son had been diagnosed as being PI. Negative sweat test, he had a full genetic test that came out with nothing. We kind of forgot about CF. His genetic test had been done at a local lab, that I know well and I know they take shortcuts on other protocols, I have lost my trust in them.

My son is now 4. His last fecal elastase dipped (92, still high compared to regular CF kids, but he used to be at 150) and a 72 hours elastase test came out as bad (proving definitively that he has a pancreas problem). His symptoms are all digestive, lots of diarrhea, has been on ZenPep for years. He also has reflux if we forgot to give him his Prevacid. Now he is going to take these special vitamins for CF kids. His new GI is really leaning on CF, we're having a battery of test coming to basically rule out other diagnostics that could explain his pancreas problems.

We are also referred to a lung doctor, a new sweat test is scheduled as well - to a different place than before, we just moved to a different state.

Anyway there probably will be a discussion about a new full genetic test to test for rare mutations (well I will push for it, that's for sure). I know Ambry was THE place before: is that still the case? Other very good sequencing centers for CF that you can recommend? We are now in Texas.

 

[Julie7]

Sanfloraine, I think others would sugfest a certified CF clinic. I think it is impotant to ensure the right genetics are ordered.
Full genetic screen mutation (2500+ mutations including poly T variants) plus a deletions and duplicatiins test (considered separate).
You might want to ask for genetic screening for others diseases besides CF. There are mutations for PCD and pancreatic disorders.
92 on a fecal elastase is plain low. I would not compare a 92 to another number, only relative to your child over time and the fact that it is below 150. My child's CF dr doesn't like anything below 300 (though he is not formally CF diagnosed).
Once you agree on the tests...then ask where it goes. Finally, expect to wait a few weeks for results.
Best of luck and I would demand this.

 

[Justinsmama]

Hi,

My son was only recently genetically confirmed with CF. We were in the same spot as your child. When he was first tested two years ago, he had one mutation, three poly's and something with 7t/11t. One of his poly's is now considered disease causing. Justin's first fecal elastase test was 148, then 6 weeks latter it was 70, then 25. His dropped quickly. He had just turned 6. Looking back, he had problems before that. Between 4 and 5, he actually lost a pound and went from 48% for weight to 15. By the time we got him on enzymes as almost 7, he was below 3% for BMI. I agree with Julie about what tests need to be run. I am not sure it matters so much where (as long as CF approved but those are the tests that need run. Good luck!!!

 

[Justinsmama]

Hi,

My son was only recently genetically confirmed with CF. We were in the same spot as your child. When he was first tested two years ago, he had one mutation, three poly's and something with 7t/11t. One of his poly's is now considered disease causing. Justin's first fecal elastase test was 148, then 6 weeks latter it was 70, then 25. His dropped quickly. He had just turned 6. Looking back, he had problems before that. Between 4 and 5, he actually lost a pound and went from 48% for weight to 15. By the time we got him on enzymes as almost 7, he was below 3% for BMI. I agree with Julie about what tests need to be run. I am not sure it matters so much where (as long as CF approved but those are the tests that need run. Good luck!!!

 

[LittleLab4CF]

A full amplified CFTR genetic test includes 1900 +/- mutations is what you want. Contacting the CF Foundation at CFF.ORG you can talk with your State chapter to find the closest approved CF center. I was seeing a pancreatologist when my CF test was ordered and he included tests for pancreatic CF like Spink1 a mutation purpose built to nail the pancreas. I have CF and I am technically a carrier. My mutation (S1235R) is known to cause pancreatic CF in single copies. I also have a 7T,7T polymorphism and there's a possible correlation with CF. A contributor accurately noted that T polymorphisms are quite common outside of the CF population. That said, CF specialists are finding CF or CRMS when nothing more notable than a 5T or higher polymorphism(s) are showing up in comprehensive testing.

I will try to locate my first test to see if any other special assays were done. Clinical presentation trumps everything else from sweat chloride to genetic testing. Even still, the test was available in 1992, CFTR gene testing went from a pretty manual process that easily misses a mutation or thousand to complete assays. A mere fraction of the mutations are completely vetted.

Idiopathic pancreatitis was my initial diagnosis prior to genetic testing. It's reasonably certain that the pancreatitis is genetic in origin. If there are supporting issues like small duct disorder and head, sinus and possibly lung infections and more GI misery than most anybody, a CF or CRMS diagnosis and treatment protocol is in order. Because so many genetic drugs are in the pipeline it is well worth the test now.

Don't put too much importance on this "test".

LL

 

[sanfloraine]

Thanks you all for your answers.

Since I posted this post a week ago, my son has now developed lung problems. Bad cough with thick yellow mucus, he had a full bacteria throat test that came out positive for abundant and free positive cocci, we were told he is at risk of developing pneumonia. He is now on Clindamyocin. We were also told regular people do not get this type of bacteria... Arnd are about to be referred to a CF lung doctor faster than planned.

We are dazed and so stressed, first his fecal elastase that goes down and now some serious lung problems. If it's not CF then what else? LittleLabForCf you are so right to say clinical presentstion trumps everything else and I wish this stupid CF professors we saw 2 years ago had been able to focus on his symptoms instead of focusing on his negative sweat test and his "high" fecal elastase of 150 as well as his inconclusive genetic test. He had the very bad diarrheas only CF patients will get (before starting ZenPep) and a sinus infection at 15 months old plus a total of over 20 ear infections. And a mild touch of 'asthma'.

I will try to have a new genetic test for him at a certified CF clinic, but right now it's not top on our priority list.

 

[Julie7]

Would suggest the CF lung pulmonologist orders the genetics aa this should be a priority as well as stabilizing and treating his current lung problems. Stay strong!

 

[Aboveallislove]

I agree with Julie. While you want to get the treatments going strong and the genetics will tell you whether kalydeco might help, for instanc if the mutation is a residual function one or a gating one, etc.

 

[JENNYC]

I just read that you are in Texas. I wanted to let you know that Texas Children's Hospital is amazing. They have state of the art equipment and caring doctors. And as far as CF goes we have been very pleased with them keeping up with all the latest technology and research. I hope that you can get everything sorted out for your little one. I know it seems like you are in a never ending whirlwind. Prayers and Hugs!!!

 

[julie]

Ambry genetics http://ambrygen.com/tests/cystic-fibrosis-testing has the most comprehensive testing available.

 

[sanfloraine]

Thank you everybody! Well we now know that my son had a sinusitis, he had a throat culture that showed some bacteria but nothing specific to CF. We had to go to to the ER, the doc was great there and put him on the right antibiotic. He is now followed by a good lung doctor specialized in CF... but they still don't know if he has CF or not, kind of a mystery diagnostic. I'll make another post about that.