Sometimes in my posts I refer to Little H as being undiagnosed and mention Swan (syndromes without a name) and at other times I mention his rare chromosome disorder and refer to Unique. You must wonder then ,how we can fall in both camps - we either have a diagnosis of a rare chromosome disorder or we don't, right?
Well it's not that simple ...
Inside every cell of our bodies (except the red blood cells) we have a nucleus and inside this are chromosomes. They're long and thread-like in structure and are made up of DNA and proteins. Special stretches of DNA are genes and it is these genes that tell our bodies how to develop and how to function properly.
Apart from the the egg cell in the female and the sperm in the male, each cell normally contains 23 pairs of chromosomes, that's 46 altogether. They are named as numbered pairs from 1-22 and the 23rd pair are called the sex chromosomes, labelled X or Y. Males usually have an X and a Y, whereas females usually have two X's.
Chromosomal abnormalities can occur when there are extra chromosomes (for example Down Syndrome) or missing chromosomes. They can also occur when the chromosomes are rearranged and small parts of the chromosome are added or deleted - this is known as micro-duplications or micro-deletions.
Sometimes the chromosomes just get a bit mixed up - this is called a translocation and as long as there is no material missing or added (a micro-deletion or micro-duplication) then this shouldn't cause any problems at all. Many normally functioning members of the public may unwittingly have these 'balanced translocations' with little or no effect.
H appears to have a balanced translocation. in six different places, his chromosomes have broken and reattached somewhere else, though there is no evidence of any material missing. On the face of it he shouldn't have any problems at all. But clearly he does. And since with every break point, the chance of losing a small amount of genetic information increases (even if we can't see it yet) the fact Little H has six mean that it is highly likely that at least one of these breaks is the cause of H's difficulties.
To have chromosomes as dramatically rearranged as H's is quite unusual. At present there is no-one else in the world with his exact rearrangement of chromosomes. He is entirely unique! In time, with greater chromosomal analysis we may be given a series of numbers and letters which indicate the specific point on the chromosome that is responsible for his special needs and then we may find someone else with a deletion in the same place, but for now, as far as we know, he is entirely one of a kind.
Most of this was paraphrased from the Contact a Family directory. You can find out more about chromosomal abnormalities by clicking here.