Part 1 of Essay
Down syndrome is one of the most frequently occurring birth defects in the world. It is a chromosomal abnormality which results in 47 chromosomes, instead of 46, with an extra chromosome being 21. Because the majority of Down syndrome cases affect the twenty-first chromosome, it is commonly called "trisomy 21." Down synd ....

Part 2 of Essay
.... with 47. Translocation occurs when part of the twenty-first chromosome breaks off and attaches to another cell. The total number of chromosomes is 46, however the excess material from the twenty-first chromosome results in the affects of the syndrome. With translocation, most cases occur sporadically, with no bearing on maternal age. These two types of this syndrome are very rare, being responsible for only 6 or 7 percent of all cases. Children with Down syndrome are at high risk for health proble ....