Trisomy 21 is an inherited disorder with a genetic predisposition. If a parent has Trisomy 21, the offspring are 50% more likely to have Trisomy 21 than other healthy children. Trisomy 21, also known as Down syndrome, is a chromosomal disorder caused by an abnormality of chromosome 21, which is characterized by mental retardation, peculiar facial features, growth retardation, and multiple malformations. In general, the older the pregnant mother is, for example, older than 35 years, the higher the chance of developing trisomy 21 is significantly higher. There is no effective treatment for this disorder, and it is recommended that mothers prevent it effectively through prenatal screening.