Humans typically have 23 sets of paired chromosomes in our cells that carry genetic material, or DNA. This DNA gets translated into traits such as our hair and eye color. Down syndrome is a condition that results from having all or part of an extra chromosome 21. It is sometimes referred to as trisomy 21, meaning 3 copies of this chromosome, but we now know it is often caused by other variations. This chromosome arrangement occurs before birth, and Down syndrome is usually identified at birth.
It is found across all races, sexes, and socioeconomic status, with a frequency of about 1 out of every 700 births in the United States. It is the most common chromosomal condition, with about 6000 babies born per year with Down syndrome. The likelihood of having a child with Down syndrome increases with maternal age.
The additional genetic material affects development, and results varying degrees of intellectual and physical delays and disabilities, as well as an increased risk for associated medical conditions, which I’ll describe further.
People with Down syndrome often have certain similar physical features, including poor muscle tone, flattened face, upward slant to the eyes, a single palm crease, and short stature. However, just like anyone else, people with Down syndrome are all unique individuals, with unique characteristics!
People with Down Syndrome will have some cognitive delays, but the degree of intellectual disability is usually mild to moderate, allowing them to be integrated into the community, including school, work, and social settings. Speech often develops more slowly, and may be difficult to understand.
As to the physical disabilities, about half of children with Down syndrome are born with a heart defect. Some may have intestinal blockades. Other chromosomal conditions are associated with changes affecting chromosome 21, and persons with Down syndrome are at increased risk for these conditions, including leukemia.
People with Down syndrome also have an increased risk for other medical conditions, including: gastroesophageal reflux (heartburn); hypothyroidism (under active thyroid;) celiac disease (intolerance for wheat); Alzheimer disease; and hearing and vision problems.
There are many myths and fears about having the diagnosis that a little education can help dispel. There is no medication for Down syndrome, though treat