What is translocation Down syndrome?
Translocation Down syndrome refers to the rearranged chromosome material. There are three # 21 chromosomes, just like there are in trisomy 21, but one of the 21 chromosomes is attached to another chromosome, instead of being separate. The extra # 21 chromosome is what causes the problems that make up Down syndrome. In translocation Down syndrome, the extra 21 chromosome may be attached to the #14 chromosome, or to #s13, 15, or 22. In some cases, two #21 chromosomes can be attached to each other. Three percent to 4 percent of babies born with Down syndrome have translocation Down syndrome. If you had a roomful of 100 babies with Down syndrome, they would all look alike and have similar features and health problems. You would not be able to pick out the three or four that have a translocation. Whenever a translocation is found in a child, the parents’ chromosomes are studied to determine whether the translocation was inherited or not. If one parent has the translocation chromosome, then
