Whole Exome Sequencing

Dealing with Wendell’s health issues is one reason I did not write last year.  I wasn’t sure whether I wanted to publicize the new findings.  I am also not one to seek sympathy or pity either. I’m ready to share now because what I’ve learned and am going through might help someone else.  Wendell is 16 now, so it’s a long story. So, let me get to it.

Wendell was delivered by C-section at 36 weeks because my OB-GYN didn’t like my belly measurement, and an ultrasound estimated his weight at 4 pounds 8 ounces.  He actually came out at 3 pounds 14 ounces.  He had a full head of hair, probably spent all his time growing that hair instead of the rest of him!

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Immediately, doctors discovered a low platelet count and transported Wendell (without me) to the NICU at another hospital for treatment and further testing.  I was stuck for 3 days before my doctor released me, and then I still couldn’t drive myself to the other hospital.  The husband had to drive me up to the hospital at least twice a day so I could spend as much time as possible with him during visiting hours.  If you’ve never had a child in the NICU, you don’t realize that even as a parent you are limited to visiting hours!

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He spent 4 weeks in the NICU where they ran a battery of tests.  It was discovered he had a brain hemorrhage, but never determined if it occurred before, during birth, or after.  (It has since been reabsorbed into the brain tissue, but evidence still appears on a MRI.)  Also discovered were the heart defects, ASD, VSD and PDA; I won’t detail these because they healed spontaneously without surgical intervention before his 1st birthday.  Wendell never developed the suck, swallow, breathe reflex, so he would not feed from a bottle.  He was fed through a nasal gastric tube (NG-tube), which we had to learn how to insert it and test for proper placement before we were permitted to go home.  When we were sent home, we had a heart and lung monitor for use at night, and a continuous feeding pump.

First night at home

First night at home

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6 month

Time passed, specialists were visited, tests were run, syndromes were ruled out.  Every milestone was delayed; he sat up at 8 months, I can’t remember crawling or standing, but he didn’t walk on his own until 30 months.  I also don’t remember words or phrases, because nothing came when or as expected. Gross and fine motor skills were severely delayed.  Receptive and expressive language skills progressed well behind his chronological age.

After 11 months, replacing the NG-tube was growing more traumatic for me and Wendell, so we went to the gastroenterologist who placed a Gastrostomy tube in Wendell’s stomach.  We continued with the feeding pump for a time, but gradually increase bolus feeding during the day in order to totally eliminate the feeding pump at night.  He wouldn’t eat much by mouth, certainly not enough to sustain his life.  And his weight was always below the 5th percentile.

At 27 months, he tested low for growth hormone and hypothyroid, so we started daily growth hormone shots and thyroid medication.  Slowly, his weight and height began to catch up, and I do mean slowly.

In 2003, before Wendell’s 3rd birthday, he was to be transitioned from Early Intervention services to the California Public School System.  He was tested by several psychologists, and was deemed to qualify for Special Education Services in our school district based on “moderate to severe Mental Retardation”.  (Side note, from this point on, I will use the currently accepted term, Intellectual and Developmental Disabilities or ID/D.) This was a complete shock to me because no one, not even Wendell’s pediatrician had ever hinted at that diagnosis.  Everyone said he’d catch up, but of course he never did.  It was at this time that his pediatrician gave me a copy of Emily Perl Kingsley’s essay Welcome to Holland, for which I have always been grateful.

In 2005, Wendell and I moved to Pennsylvania and his dad and I divorced.  We found new specialists, did I list the fields? Wendell sees physicians in Gastroenterology, Endocrinology, Neurology, Pulmonology, Psychiatry and Genetics, in addition to his Pediatrician.  We continued with genetic testing every couple of years because there just wasn’t anything new.

In 2007, Wendell developed a seizure disorder, at least that was the only thing that ever came out of the incidents.  Twice he was flown by helicopter to Geisinger Children’s Hospital.  The first time we spent 5 days there, 3 days at home then the 2nd flight back and we were there for 2 weeks.  Suffice it to say, that was not a pleasant experience.

Before G-tube removal

Before G-tube removal

In 2010, I wanted to get him off of tube feeding, so we spent a month at Hershey Feeding Clinic. The G-tube was removed in 2011.

Moving on, in 2015, the geneticist recommended Whole Exome Sequencing.  WES checks for misspellings in the genetic code of more than 20,000 protein-coding genes in the genome.  The geneticist explained it as looking for spelling errors or deletions on the pages of a book, a very large book.  In order to obtain the best results, samples are taken from both parents to determine if any mutations are inherited, or occurred spontaneously, de Novo.  Four months later, we had results.

I passed on 2 mutated genes.  The 1st causes a condition called Dyskeratosis Congenita, a rare, genetic disorder affecting bone marrow and blood production, put simply.  The 2nd causes Congenital Long QT Syndrome, a heart arrhythmia disorder.  Both of these will be explained in future posts.  Neither of these syndromes or diseases explained Wendell’s intellectual and developmental delays.  At this point, we had some answers, but not all the answers.  We did add several new specialists to our list, Hematology/Oncology, ENT, and Dermatology.

One of the mutated genes is the SON gene.  The mutation here is de Novo, meaning not inherited.  At the time we got our results, this significance of this gene was unknown.  A few months later, our geneticist contacted us for permission to include Wendell’s data in a study being conducted by the Mitchell Cancer Institute at The University of Southern Alabama to determine if mutation of the SON gene could be linked to Leukemia.  This study, and one conducted at Baylor University at the same time concluded that the de Novo mutation is linked to intellectual disabilities.  I just learned that a total of 4 studies have reached the same conclusion, and the resulting information has given a name to this syndrome, Zhu-Tokita-Takenouchi-Kim Syndrome, or ZTTK.  The article can be found here.  One of the parents even set up a Facebook page so we can share our stories and support each other through the years.

Waiting 16 years to find a reason for Wendell’s issues, all of them, is such a relief.  Having 3 separate and unrelated diagnosis’ can be stressful too.  But finally knowing what they are gives me a road map of what to expect and how to plan for his future as he ages and his conditions progress.  All part of the journey.

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