I've read many of the recent medical journal articles about GLHS, and as of February 2008 there were apparently only 19 people world-wide who had been diagnosed with this syndrome.
And Emma is almost certainly #20. So here I've been thinking that she is SO incredibly unusual in that she has both TAR Syndrome and GLHS.
Then I joined the Yahoo Group for parents of children with cerebellar issues.
I discovered within a few weeks that there are at least 2 other children whose parents/guardians are members of that group who also have GLHS. I also received an email recently from the mother of another Emma who probably has GLHS.
But the really interesting part is that, out of these 4 children that I know about (my Emma, the other Emma, plus the two kids through the Yahoo group), TWO of them have both GLHS and at least one missing radius bone (my Emma is one of them, obviously).
So I'm convinced that (1) there is a fundamental genetic connection between TAR Syndrome/radial ray defects and GLHS that has not yet been noticed by the medical research community, and (2) GLHS may not be nearly as rare as previously thought.