N1303K + G542X Mutations = Phenotype?

[Mommymonster]

I am currently 15 weeks pregnant and recently learned I have one N1303K mutation and my husband has one G542X mutation. I am scheduled for amnio tomorow to find out if the fetus has both recessive genes (the chances are 25% in my understanding). I was wondering if anyone out there by chance has the 2 specific mutations my husband and I have (or are homozygous for either?) and if so, if you can tell me about your CF. I know phenotypes can vastly differ even with the same genotype, but I am trying to wrap my head around what it would be like for our child if they do get both recessive genes. We are going to a genetic counselor, but I'd also like to hear from real people experiencing CF. I am new to the CF world, so please forgive me if I am not using the correct words.

 

[Beccamom]

I wish you the best at your appointment tomorrow. You came to a great place for support. You are correct your baby has a 25% of having CF, 50% chance of being a carrier, and 25% chance of having no CFTR mutations. I don't have the gene combination you mentioned, but my understanding is that even with the exact same genes and even in the same family CF patients all present differently. If your child does have CF knowing before he/she is born means you will have access to the best possible care right away which will mean the best long term outcome for your child. If you find out that your child will have CF we are all here for support.

 

[welshwitch]

Hi Mommymonster,

Beccasmom is correct--genotype does not predict phenotype. However, I have ONE of the mutations you describe and I am a healthy 32 year old woman who works full time and has over 100% lung function. So that's my experience

I wish you luck if your child does have CF--this is a great website to come to if s/he does.

 

[bdspiek]

I am currently 15 weeks pregnant and recently learned I have one N1303K mutation and my husband has one G542X mutation. I am scheduled for amnio tomorow to find out if the fetus has both recessive genes (the chances are 25% in my understanding). I was wondering if anyone out there by chance has the 2 specific mutations my husband and I have (or are homozygous for either?) and if so, if you can tell me about your CF. I know phenotypes can vastly differ even with the same genotype, but I am trying to wrap my head around what it would be like for our child if they do get both recessive genes. We are going to a genetic counselor, but I'd also like to hear from real people experiencing CF. I am new to the CF world, so please forgive me if I am not using the correct words.

N1303K causes improper folding the the CFTR protein. The G542X mutation causes a premature stop codon in the CFTR mRNA. These are two different classes of mutations. N1303K mutation is considered a severe mutation with respect to the pancreas. My girlfriend has both of these mutations. She was a full blown diabetic before she reached her teens due to the N1303K mutation. With respect to lung function, she performed better than me (individual without CF) on her Pulmonary Function Test her last visit to the hospital. She has no problem keeping up with me and usually outruns me on the treadmill during our nightly runs. I listen to her lungs on a regular basis has never hear the common "crackling" sounds you hear with other individual's lungs with CF. She honestly has more health related problems with the diabetes more than the CF. I do imagine running on a daily basis and eating a healthy diet has tremendously helped her overall health over the years though. Shes pretty used to the routine of the daily breathing treatments. I've recommended particular antibiotics to combat the effects of the G542X mutation. Aminoglycosides can effectively lead to a fully functional CFTR protein by combating the premature stop codon associated with the G452X mutation. The months she is on Tobramycin, you see a complete turn around on any complications she was having the previous month. She visits Northwestern Hospital every 9-12 months for her week of antibiotics. Other than that she has a completely normal life. She works 30 hours a week at a pharmacy, studying for a masters in education, exercises everyday, and still manages to spend time with me. We have the disease down to a science and living with it doesn't effect either of our lives. Every mutation is different, but I can tell you I'd rather her have these than any others. I've seen many other CF'ers at Northwestern Memorial and she is always by far the healthiest.