Thursday, December 16, 2010

OTC Deficiency - A Genetic Abnormality

My husband likes to tease and tell people that I'm a mutant.  It's not really wrong.  It's true!  I'm missing an enzyme that tells the body how to metabolize (use) protein properly. 

There's a name for what I have.  Don't worry, I don't expect you to remember it.  It's Ornithine Transcarbamylase Deficiency, typically denoted as OTC Deficiency.  If you really want to remember it, just think OTC - Over The Counter.  If you watch House, you might have heard of it.  In the very first season, one of the characters had OTC Deficiency.  I didn't see it, but apparently it had to do with a man who got sick, his brother snuck a steak into the hospital for him to eat, and then he got much more sick!

I've known about this since I was 4.  I have this lovely family memory of going to Ponderosa (does Ponderosa exist anymore?) and getting to eat jello while none of the adults cared what the kids ate.  It was nearly the whole family on my mom's side there...grandparents, their 5 kids and spouses (ok, maybe 4...I think one was missing) and numerous grandchildren, of which I was one. We had all just had our blood taken to be analyzed.  ALL of us!

At that point, in good ole 1981, my mother had had two pregnancies after I was born.  With each, she had a boy who was fine upon birth, and then hours later got sick.  Each lived for 3 days.  Her sister had also had a boy.  Same thing.  Fine at birth, got sick, died on day 3.  And my mom had been a twin, but her fraternal twin brother had also died on day 3, and he had been the larger, healthier baby at birth.

All of these births were diagnosed as SIDS - Sudden Infant Death Syndrome.  The family got together, contacted the health unit and said, Listen...this is not SIDS.  There is obviously something more here, since there have been 4 deaths of baby boys in the same family.  The doctors did some investigating, decided that there was a potential that it was OTC Deficiency, and that's how we all ended up going in for blood work.

Turns out that OTC Deficiency is an X-linked metabolic disorder.  The boys are more highly affected (in my families case that means neonatal [newborn] death), because they don't have the extra X chromosome to make up for the defective one if theirs is defective.  It's a 50/50 chance of the baby getting the defective gene with the missing enzyme.

So all in all, the odds are like this.  25% Healthy Baby Girl.  25% Carrier Baby Girl.  25% Healthy Baby Boy.  25% Affected Baby Boy (in my family = neonatal death at 3 days old).

We know that my grandmother was a carrier (but don't know about HER mother).  Grandma had 6 kids.  4 girls - all carriers, 1 boy unaffected, and 1 boy (mom's twin) who died.  In my generation, although there are many grandchildren, only two of us are female carriers.  The other one has decided NOT to have children, partially or all because of the fact that she is a carrier herself.

That leaves me.  And a story to be told in a future post.

1 comment:

  1. Wow! Thank you for posting this. I've been thinking of you. All the best for a happy and uneventful pregnancy :) xoxoxo

    ReplyDelete

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