Re: [MLUG - DISCUSSION] Holt-Oram Syndrome

[Mike Miller <EMAIL:PROTECTED>]

On Wed, 12 Mar 2008, Vern Green wrote:

> > 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.

That's right.  Cytogenetic analysis is the chromosome test.  I feel a 
little better about them now that I know they already did that.  They 
didn't notice the hand problem though, even though they were looking at 
the palms.

They should look into Holt-Oram for you.  Apparently, there are strict 
clinical diagnostic criteria that can almost always rule out kids who do 
not have TBX5 mutations:

http://www.ncbi.nlm.nih.gov/pubmed/16183809
http://www.ncbi.nlm.nih.gov/pubmed/17534187

I don't know a thing about "radial ray deformities", but it sounds like 
that is thing to study before looking for TBX5 mutations.  Or maybe the 
nonopposable thumb *is* a radial ray defect.

Kids who meet strict criteria have identifiable TBX5 mutations about 1/2 
to 3/4 of the time, but there might be more mutations yet to be discovered 
that will increase that percentage:

http://www.ncbi.nlm.nih.gov/pubmed/16917909


> > > 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.

I think Jon found the answer on that one.

Mike

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