6q26 Micro-deletion

Hi everyone.  Today’s post is going to be a bit of a long one.  I want to explain something in detail to our friends and family, but also want to make sure I document it well for my own reference in the future.  I also hope this contributes to the medical community, or other parents, who may have a similar thing their child is going through.

Early in January, 2016, one of the doctors at John Muir suggested that we may want to get a genetics test for Samuel.  They were concerned that he wasn’t pacing as quickly as Jacob or Charlie, and they thought a genetics test would be helpful to rule in or out some things.  So they pulled some blood on January 20th and sent it away for a genetics test.

The results took about three weeks to come back, and Dr. Tran finally got them on February 9th.   We learned about this as Samuel was in his PDA Ligation surgery.  Of course that’s the surgery that not only fixed his Patent Ductus Arteriosus, but also paralyzed his vocal chord.  We took her call literally while Samuel was under the knife inside the Benioff Children’s hospital.  Kristen and I did the call on my iPhone speakerphone, in a courtyard behind the hospital.

In short, Dr. Tran shared that Samuel had something called a genetic “micro-deletion”.  As you may expect, a “micro-deletion” means there’s a small amount of DNA that’s missing.  Originally she referred to a broad name of a PARK2 gene, but we got very specific information a bit later.  Officially, Samuel is missing 351,219 base pairs in Chromosome 6, sub-section 26.  We know this as a 6q26 micro-deletion.

The blood test results that came back show the following:

arr [hg19] 6q26(162,510,973-162,862,192) x1

Heres the breakdown of this reading:

arr – This indicates a chromosome Microarray test was performed

hg19 – This refers to the version of the human genome that was used for the test.  As the genome is mapped, more information is available, allowing more exact results.

6 – The chromosome

q26 – The section where the missing material should be

162,510,973-162,862,192 – This is the “from” and “to” material that’s missing.

x1 – This means there’s just one copy of base pairs on each side of the chromosome, as you’d expect.

Genetics 101

screen-shot-2017-02-08-at-2-17-05-pmI’m not billing myself as an expert, but I’ve done a fair amount of research on this topic the past year, looking for answers.  As such I’ve learned a lot.  Of course you may remember from biology class that each human typically has 46 chromosomes.  23 are from the mom and 23 are from the dad.  The last chromosome, Number 23, is an X from the mom and either an X or a Y from the dad that determines what sex you are.

Within each chromosome, there are base pairs of DNA.  These are the building blocks and instructions that tell the body what to do, how to grow, etc.  There are about 3,000,000,000 (3 Billion) base pairs in each person, spread across those 23 pairs of chromosomes.  If you just focus on chromosome 6, there are approximately 171,000,000, or about 5.5% of all the DNA in your body.

Chromosome 6 is also broken into two “arms”.  The short arm is called the “p” arm, while the long arm is called the “q” arm. (In case you’re wondering, “p” was chosen as an abbreviation for “petit”, while “q” was chosen because it’s next in the alphabet.  Makes little sense to me, but whatever.)  The short backstory is that the gap between the “p” and “q” arms is where the chromosome is attached to the spindle during cell division.  Let’s not get too medical and just leave it there.

Samuel has his micro-deletion on the long-arm “q” section of chromosome 6, in a sub-section known as 26.  There are only 27 sections on this chromosome, so he’s missing some DNA on the far end of this arm.  351,219 base pairs sounds like an awful lot of missing DNA, but remember this is out of 171,000,000 base pairs in this chromosome and 3 billion overall.  Specifically, Samuel’s deletion is from base pair number 162,510,973 to 162,862,192.

So what does all this mean?

We’re not entirely sure what all this means yet.  I’ve joined groups on Facebook for those who have deletions, and I’ve searched the Internet extensively to see who else is missing this.  We’ve talked with a couple geneticists and Samuel, Kristen and I submitted some blood for extensive genetics testing (called Whole Exome Sequencing).  Frankly, Kristen and I may end up learning things in this test about our own bodies that may be forecasting future problems like cancer, Alzheimer’s Disease, etc. So we’re a bit frightened to see what comes back.

The blood test results we should get in March will hopefully have some answers, or at least be able to further narrow things down, or be able to tell more definitively what we may have to deal with going forward.

There are all sorts of other children and people who are missing sections of 6q26, though the deletions are much larger (i.e. millions or tens of millions of missing pairs).  We’ve also seen examples of people who are missing multiple sections (i.e. 6q26 + 6q27), or who have duplicate genes too.  There are many different mutations that we’ve seen. But we haven’t found anybody who has such a tiny deletion, nor have we found anybody with the exact deletion, or reasonably close to the overlap.  I posted the specifics on this page in case somebody comes across this and has something similar with themselves or their family.  We’d love to talk with you!

Obviously the most interesting thing that Samuel is coping with is his Hypotonia, but since he’s still developing and can’t talk to us yet, we’re not sure what else we may be in store to deal with.  We’ve seen others with 6q26 deletions showing symptoms of Autism, inability to speak until various age ranges from 3 or 4 all the way up to not being able to effectively communicate into high school.  We’ve seen people who have some deletions who can’t go to the bathroom, have motor skill issues, etc.  So we’re not sure what we’re in for.

For now, we continue to work carefully with Samuel on his physical therapy, occupational therapy and speech therapy.  He’s showing great signs of progress almost on a weekly basis.

If you know something about this micro-deletion, or know of somebody who has something in 6q26, please feel free to contact us directly.  We’d love to hear what your journey is or has been, and happy to share what we know at this point.

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December 23rd – Two Weeks Old

We’ve made it to the two-week mark and the boys continue to progress nicely.  There’s no end in sight for the hospital, but it’s now part of our daily routine and we can see real changes in the past two weeks.

First, we went to our two-week visit with Dr. Won this morning.  Kristen’s C-section cut was reviewed and the glue was removed.  I have to say it’s a work of art.  I’m fairly certain nobody will ever know she has a C-section.  It’s really, really good.  Dr. Won did a great job in putting her back together.

Dr. Won also told us the lab report on the placenta’s came back, and she now knows what caused the premature birth.  Jacob’s placenta was starting to get infected, so it ruptured.  We don’t know what caused the infection to start, but the rupture is a natural reaction to protect the baby from the infection.  That’s what started everything.

OK, on to the kiddo’s.

Samuel

(Note: Thanks Mom for pointing out it’s not Sammie with an IE as I typed earlier in the week, it’s Sammy with a Y)

Sammy is doing just fine for 32 weeks, 5 days, but when compared to his brothers he’s not doing as well as quickly.  He’s tied for the lead when it comes to weight: 3lbs, 4oz.  He’s not as long as Charlie though.  He’s only gained a fraction of an inch.

Today the cardiologist did an echo on his heart to see if this is impacting his breathing.  The pediatric cardiologist stopped by and told us everything looks good.  He has a PDA – a hole in his heart – but it’s normal and no concerns.

Samuel is back on the light therapy for jaundice.  He’s the only baby still in this but his numbers for bilirubin are improving.

Samuel goes through light therapy.

As we were visiting today, Sammy lost the rest of his umbilical cord, so he has a normal belly button now.

Jacob

Jacob is doing the best of everyone.  The nurses tell us his apnea and brady’s are occurring less – none overnight last night.  That’s great news.  He weighs in today at 3lbs, 4oz and he’s at the maximum feedings.  He’s technically 10 grams heavier than Samuel.

Today he started breastfeeding and Kristen says he was a champ, fully latching off and on for about 30 minutes.  That’s great news.  We’re not sure how much he took in, since the suck/swallow reflex is just building up.  But it’s possible and likely he got something.  We’ll keep working on this and build his skills in the next few days.

Jacob also lost his umbilical cord today, so he can finally get a real bath.  We’ll do that tomorrow.

Charlie

Charlie is doing really well too.  He’s weighing 3lbs, 3oz today.  He had some medicine to help that artery close off and that worked well.  It wasn’t completely closed when the doctors checked on Monday, but it was so small it was barely noticeable, so there’s no other medicine to take.

IMG_7464
Charlie chills after a diaper change.

Charlie’s vapotherm is down from 4 liters to 3 liters to 2 liters today, and he’s constantly on room oxygen (21%).  If he keeps this pace up he’ll be off all oxygen supplements in the next few days.

He’s taking his feedings like a champ.  In fact I changed his diaper at 1:45pm on Wednesday and the nurse tested for “residual” – the amount left in the stomach ~2+hours after feeding, and there’s nothing there.  So she was going to warm up his food early so he can have some more earlier.

Once he’s off his vapotherm, he can try breastfeeding with Kristen.  We introduced him to breastfeeding today but he was cranky.  He preferred to sleep during his feeding.  I managed to get a quick photo of him as he was about to doze off and close his eyes.

Charlie spends time with his mom.

After these pictures were taken, and later today, Charlie pulled out his feeding tube, so they re-inserted it through his nose.  He seems to like that better.  I also changed his diaper a bit later after his feeding and reality has set in.  This is the champion pooper of the year!  Wow.  Reality smacked me in the face today.

These boys are great and we love them like you can’t imagine.  We absolutely can’t wait to get them home.