Down’s syndrome, called congenital dysmorphism, is an autosomal aberration and is the most common type of pediatric chromosomal disorder. Some children are aborted in early fetal life. Trisomy 21 is the most common chromosomal variant and is not directly related to ethnicity or standard of living. Most children with Down’s syndrome are severely mentally handicapped and have lower than normal intelligence, which is why Down’s syndrome is also called congenital dysmorphism. Some children with Down’s syndrome have normal chromosomes, but they are heterozygous and have similar expressions. A small number of children with Down’s syndrome are chimeric, meaning that some cells have normal chromosomes and some cells have abnormal chromosomes, which are trisomy 21. Down syndrome is also known as trisomy 21 because of the severity of the abnormal cell count. Patients with Down syndrome have a low life expectancy and a short life span, and the average age of survival is not high. At present, pregnant women can be initially screened by checking peripheral venous blood at 16-20 weeks of menopause to determine if they are at high risk for Down syndrome, and non-invasive DNA or amniocentesis is recommended over the age of 35 to effectively reduce the birth of Down’s syndrome children.