The six sites are the Metropolitan Atlanta Congenital Birth Defects Program conducted by the CDC, the University of Arkansas for Medical Sciences, the California Department of Health Services, the University of Iowa, the New Jersey Department of Health, and the New York Department of Health. Approximately 5,000 children with Down syndrome are born each year. One in every 800 to 1,000 children is born with Down syndrome. But the odds increase dramatically as the mother ages. At age 45, the incidence becomes approximately one in 35.
Experts describe Down syndrome as a constellation of conditions.
Most people with Down syndrome are mentally retarded. Half of individuals with Down syndrome are born with congenital heart defects. The majority of these heart defects can now be surgically corrected. Individuals with Down syndrome have a 15 to 20 times greater risk of developing leukemia. Normally, the number of chromosomes is reduced from 46 to 23 during this process.