Down syndrome is the most common form of intellectual disability in the world. It occurs in approximately 1 out of every 1000 babies born alive. Down syndrome is a condition in which a baby is born with an extra chromosome number 21. The extra chromosome is associated with delays in the child’s mental and physical development, as well as an increased risk for health problems.
The physical features and medical problems linked to Down syndrome can vary widely from child to child. While some kids need a lot of medical attention, others lead healthy lives.
Down syndrome, also called trisomy 21, happens by chance, can’t be prevented, and isn’t caused by anything a parent did or didn’t do. Fortunately, the health problems can be managed well, especially when found early, and many resources are available to help kids and their families.
A baby inherits genetic information from its parents in 46 chromosomes, typically 23 from the mother and 23 from the father. Chromosomes hold our genes, which carry the information that determine how our bodies look and work, including traits from our relatives like hair and eye color.
In most cases of Down syndrome, a child gets an extra chromosome 21 for a total of 47 chromosomes instead of 46. Rarely, the extra chromosome 21 attaches to another chromosome. This extra genetic material causes the physical features and developmental delays in people with Down syndrome. The features are no different if the extra chromosome is by itself or attached to another one.
Kids with Down syndrome often have similar physical features, such as:
Some kids with Down syndrome have no serious health problems. But others may have medical issues that need extra care.
Medical problems that happen more often with Down syndrome include:
Two types of prenatal tests can look for Down syndrome in a fetus:
After birth, the initial diagnosis of Down syndrome is often based on the baby’s appearance. After a baby is born, a karyotype test (chromosome analysis) can confirm Down syndrome. This is typically done on a blood sample and the chromosomes are grouped by size, number, and appearance to look for differences.
Down syndrome cannot be cured. Early treatment programs can help improve skills. They may include speech, physical, occupational, and/or educational therapy. With support and treatment, many people with Down syndrome live happy, productive lives.