I have had the genetic test done for LQT, i have tested positive for LQT 3 along with symptoms of low heart rate i just had a ICD implanted.My 9 year old was tested first, he too has LQT 1 &2 along with my first son (24 years old) has LQT3 My question is how is it possible that my one son has lqt 1 &2 and Myself & my older son has LQT3?( They have 2 different fathers)
Hello Slick5679, I am also sorry I had not answered this sooner.
It is very interesting that you should ask this question. Often many times people are tested (by blood) for genetic type testing, and I don't know initally if the results they get are inheritied forms of genetic problems, or aquired forms. In the case of LQTS there are a few ways one can have this. There is the genetic aspect which is inherited because a parent is a carrier of the gene. There is the medication aquisition, where the person can have LQTS from one of 50 different types of medications. Thirdly one can aquire LQTS from a major loss of potassium or sodium ions from the bloodstream - which comes from certain health problems such as vomiting, diareah or even aneroxia. As seen here in this site: http://www.nhlbi.nih.gov/health/dci/Diseases/qt/qt_causes.html
But if your are sure that both of your children (who are from different fathers) have genetically acquired LQTS, the only thought I have immediately is that the child with LQTS3 could have a genetic mutation from the father? Did you ever have both fathers genetically tested? I am interested to know if his father has a genetic mutation of LQTS3.
The reason I ask is, if he has LQTS3, and your genetic variant is LQTS 1&2 then your son couldn't have acquired his genetic mutation from you unless you carried the LQTS3 as a mutation also but just didn't have that variant as a dominate allele in yourself and your other son. The thing is, if he definitely has an inherited LQTS, then it has to come from one or the other parent. If his LQTS was not genetically inherited, then his could have be from one of the other ways to acquire LQTS but seeing as how LQTS 1,2 & 3 are inherited forms, this would not be.
I found a terrific site which explains both LQTS and Genetics. Only, it doesn't explain if it is possible to pass on more then one type of LQTS but not have it yourself. It is definitely possible to have several mutations, where even some are silent. So it makes me then wonder if you have LQTS3 as a silent mutation for you and your other son.... http://www.thetech.org/genetics/ask.php?id=370
I found a pretty good forum (that is answered by a genetics doctor) however I am not sure if it is still running currently. It seems to have a wealth of information regarding LQTS answered by the doctor. http://www.qtsyndrome.ch/cgi-bin/discus/discus.pl?pg=topics
I am sorry that I haven't been able to answer your question directly, but from what I know about genetics, the fact is when you pass on a variant genetically, the big question is, did your sons receive two variants or one? (Both alleles are mutated). If the answer is that they have two copies of the variant (meaning they are homozygous) it comes from both parents, and if this is the case, then both of your sons have a mutation from you and their fathers (albeit different fathers) - which would be very interesting since the chances of having LQTS is around 1:5000. Not rare, but certainly not that common. If they are heterozygous then they only have one copy of the variant.
If you would like any further information from me, you can message me directly at any time.
In addition to anything I have mentioned, please keep in mind, that while I or others may have extensive knowledge in many areas, you should always seek professional medical advice from your own physician, as it pertains to medical conditions or concerns.
Good luck, and if you have any other questions that I can help you with, please feel free to message me directly.
Sincerely, Sandi (Dragon1973) MedHelp Genetics Community Leader; Children - Special Needs Community Leader; Down syndrome Community Leader & Ds Group Forum Founder/Moderator
I jsut received a faxed copy of my sons report form the genetic lab and what i am finding out is that my son pediatric cardiologist read it wrong!! go figure. She read class 1 & class ll varients. & told me LQTS 1 & 2. He has class 1 deleterious mutation SCN5A Glu 1784 Lys.(LQTS 3) & possible class ll deleterious mutation KCNH2 Arg 892 Ser.(LQTS 2). So to sum it up , Myself, my 9 year old & 24 year old have inherited LQTS 3. I wish i could find another pediatric cardiologist , there are not many around here. The one we have is affiliated with CHOP(cildren hospitla of Philly), they are supposed to be really good???? I was very disappointed to read something other than what she told me.Thank you for all your information & responding to me. Marie
Wow! This goes to show us that doctors are not always right! They make mistakes just as we all do. The scary thing is that it caused so much confusion. Thank goodness it wasn't problematic or dependant on someones treatment....
I hope that you will be able to find another pediatric Cardiologist should you choose to leave this one. It is disturbing that she read it wrong but do remember, mistakes can happen. I am just glad that nothing terrible happened as a result. I hope that you pointed it out to the doctor so that they are aware they caused you so much confusion. Hopefully if you did point out the error, it might perk her attention up to avoid making mistakes like that in future.
You are very welcome, even though I didn't do very much in terms of answering your questions!
Hope everything goes smoother for you in future. Keep us update d if you can.
MedHelp Genetics Community Leader;
Children - Special Needs Community Leader;
Down syndrome Community Leader & Ds Group Forum Founder/Moderator
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