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 Down syndrome is usually caused by a cell division error, which is known as non-disjunction. This occurs when an embryo develops with three number 21 chromosomes instead of two. This excess genetic material alters the course of development and causes the characteristics of this syndrome. The cause of this faulty cell