Re: [MLUG - DISCUSSION] Holt-Oram Syndrome

["Jonathan King" <EMAIL:PROTECTED>]

On Wed, Mar 12, 2008 at 10:14 PM, Vern Green <EMAIL:PROTECTED> wrote:
> >
> >  The left thumb is "nonopposable" and "finger like" -- those are the terms
> > I'm seeing for that kind of thing in OMIM.  Certainly there are not many
> > known conditions that cause that trait and Holt-Oram is one of those
> > conditions.
> >
> > Do you have good health insurance?  I'm surprised that they didn't do a
> > more thorough workup.  Did they do any cytogenetic analysis?  In this case
> > they can go straight to chromosome 12 (12q24.1) and look for mutations in
> > the TBX5 gene.  I would have thought that cytogenetic analysis would
> > always be ordered when idiopathic heart defects are seen, but it isn't my
> > area.
>
> Yeah, I actually do have some good insurance. The only work up they did was
> a chromosome test, the pediatrician called for that as he saw a "*****" line
> on the palm of his hand. (I cannot remember what he called it) The
> pediatrician thought he might have mild downs syndrome, but that test came
> back negative. He did admit that the chomosome test would not detect
> Holt-Oram.

Mild Down syndrome would definitely be a rule-out to look for; it's
orders of magnitude more common than something like Holt-Oram and easy
to spot from a karyotype.

> > > You might also notice another genetic trait. This one he and I clearly
> > > share, as does my older son, my sister, and I think my mother. We all
> > > had the crooked little finger. I do not think that trait is tied in
> > > anyway to what we are seeing here with Holt-Oram, but maybe I am wrong.
> >
> > I don't know.  Is it only on your left hand?  Sometimes the same gene will
> > cause mild symptoms in some family members and more severe pathologies in
> > others.
>
>  No, it is on both hands, it is on both hands of my sister and my oldest son
> as well. I remember this coming up in school, they talked about this being a
> genetic trait, kind of like a widow's peak hair line. I was the only kid in
> my biology class that had them and everyone was quite surprised, I never had
> noticed it before then.

My brother has this, but also some other congenital tendon issues as
well. I think this is another one of the classic "biology class
inheritable traits" that has not really panned out to be tied to one
specific locus (tongue-rolling is another). I used to think that
having a "single eyelid" (like many Asians, but also some Europeans
like, uh, me) was a monogenetic dominant trait, but that's not so
clear either, as it turns out.

jking

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