Genetic testing results

As you can tell by the lack of recent posts, everything has been going very well. Audrey has been eating and sleeping like a champ lately and is really growing quite a bit. It is hard to believe that she will be 9 weeks old on Monday. The first couple of months have really flown by and we when we hold Audrey now it feels like she has doubled in size from the tiny little 5 pounder that was born on June 14. We still have the midnight and 6 am medicine dosages that we have to wake for but we have recently been letting her go as long as possible in between rather than waking her for a feeding. A couple of times this week she treated us to almost making it the full 6 hours (or really about 5.5 after getting her down from the midnight one).

We had our first intro into what our future will hold with treating any of her illnesses. When holding her one night, she felt a little warm to us. We took her temp a couple of times and it was only in the high 99's but immediately our heads start churning on the possibilities of what that night could hold if it worsens. We pulled out the long list of medications that she can or cannot have because many medications such as antihistamines or some antibiotics actually lengthen the QT interval. Thank goodness Tylenol is safe to take but just to be certain we called the CHOA Cardio 24 hour line just to talk with them about giving it to her if needed. In the first 9 weeks that was really the first time we have had to consider 'The List' but it certainly wont be the last. We will have to make sure our Pediatrician's office has it and is familiar with it anytime they prescribe anything for Audrey.

As indicated by this entry title, we were thrilled to finally get the results back from Audrey's DNA testing this week. All along the dr's have suspected she was most likely Long QT type 2 or type 3 and the test results confirmed that she is positive for type 3 based on the mutation of the SCN5A gene. Type 3 is an abnormality of the sodium ions in her heart cells. It was definitely emotional to finally get this confirmation of her diagnosis. On one hand we were unhappy to hear it was type 3 but on the other hand we were glad it was one of the known gene mutations so that there is some medical history to help guide what treatments will best help Audrey. Type 3 is quite a bit more uncommon than types 1 and 2, I have seen numbers around 5-10% of the diagnosed LQTS cases. Type 3 event triggers tend to be a low heart rate such as when one is sleeping as opposed to some of the other types that could be triggered by sudden loud sounds or events. Luckily Audrey does have the pacer which will always keep her heartrate above whatever the low end settings are.

We have only received the DNA results over the phone and have not met with our Doctors to discuss the details yet. We'll have to see how this impacts the treatment Audrey is receiving because a lot of the articles I read tend to say the beta blockers are not very effective treatment yet the Mexiletine is, which targets the sodium channels. They wanted to keep Audrey on both the beta blockers and Mexiletine until we had test results because we were having good results and we didn't yet know which type to specifically treat. There is a possibility we could back off of the beta blockers but we'll have to see. We meet with our EP doctors once again on the 26th to discuss the details of the DNA results, how Audrey has been doing, and where we go from here.

If anyone is interested in reading up on LQTS and specifically Audrey's type 3 you can find some information at these links...

SADS website

Long QT Wikipedia

Long QT.org website

American Heart Assoc - around LQTS 3 and Sodium channel

I'll try to post some new pictures of Audrey in the next couple days.

- Mark