If you look to the upper left here there is the 31 for 21 Gadget. This means all us DS bloggers out there are going to be blogging (hopefully) 31 days straight for the month of October - why? Because October is Down syndrome Awareness Month! Why 31 for 21? Well, because DS is caused by 3 copies of the 21st chromosome! If you click on my heart that says "Perfection is made with 47 Chromosomes" it will show you what the DNA of a typical person with Down syndrome looks like. I know it's Jr. High Health Class, but I think it's pretty cool... Down syndrome occurs in every 1 out of 800 births. Ace is one in 800! As some may know and those that don't I have a tattoo on my wrist that signifies how special my little man is. It is a twisted halo with Asa's name and 1 in 800 inside.Down syndrome happens at inception as cells divide, normal division is 23 chromosomes from Dad and 23 from Mom making 46. Down syndrome is usually caused by an error which occurs when the 46 chromosomes are being divided in half and an egg or sperm cell keeps both copies of the #21 chromosome instead of just one copy. If this egg or sperm is fertilized, the baby ends up with three copies of the #21 chromosome and this is called "Trisomy 21" or Down syndrome ;-) The features of Down syndrome result from having an extra copy of chromosome 21 in every cell in the body.
95% of Down syndrome results from Trisomy 21 or Nondisjunction (this is the type of DS Ace was born with). Rarely, a form of Down syndrome called "Mosaic" Down syndrome may occur when an error in cell division occurs after fertilization (1 to 2% of cases). These persons have some cells with an extra chromosome 21 and others with the normal number. There is also a third type of Down syndrome and this is called Translocation. Translocation occurs in about 3 to 4% of cases and is cause by a piece of genetic material breaking off from another chromosome and attaching itself to the 21st chromosome. This usually happens because of a parent being a carrier of extra genetic material themselves (inherited).
So kids, that has been your DS Class for the day, and what a way to kick off 31 for 21!