October is Down Syndrome Awareness month, a time to both learn more about this common disorder and to promote the acceptance and inclusion of people with Down syndrome.

Here are five things you should know about the condition:

1. Down syndrome occurs when an individual has a full or partial extra copy of chromosome 21. Most people have two copies of this chromosome, while those with three copies of chromosome 21 develop the condition known as trisomy 21. (The name Down syndrome came from the English doctor John Langdon Down, who was the first to categorize the common features of people with the condition.) This additional genetic material alters the course of development and causes the characteristics associated with Down syndrome.
   
2. The Centers for Disease Control in 2014 estimated that about 6,000 babies are born with Down syndrome in the United State, which is about 1 in every 700 babies born. In some countries, prenatal screening and liberal abortion laws combine to reduce the number of children born with this condition. For example, in Iceland in 2019, 4,452 live babies were born. But according to their government, on average, during the past 10 years only two to three children have been born each year with Down’s syndrome. That is a rate of between 1 in 1,484 or 1 in 2,226 babies born—roughly two to three times less than the rate in America.
   
3. Compared to children without Down syndrome, children with the condition are at higher risk for numerous afflictions, including hearing loss (up to 75% may be affected); obstructive sleep apnea, a condition where a person’s breathing temporarily stops while asleep (between 50 -75%); ear infections (between 50 -70% may be affected); eye diseases, like cataracts (up to 60%); heart defects present at birth (50%); intestinal blockage at birth requiring surgery (12%); iron deficiency anemia (red blood cells don’t have enough iron to carry oxygen to the body) (10%); hip dislocation (when the thigh bone slips out of the hip socket) (6%); and thyroid disease (a problem with metabolism) (4-18%). Older adults with Down syndrome have increased risk for developing Alzheimer’s disease.
   
4. The life expectancy of people with Down syndrome quadrupled between 1960 and 2007. In 1960, on average, persons with Down syndrome lived to be about 10 years old. In 2007, on average, persons with Down syndrome lived to be about 47 years old. Many factors have contributed to the increase, but the major change was the number of infants with Down syndrome that die before 1 year of age has declined over time. For example, between 1979 and 2003, the rate of death during the first year of life declined from 8.5% to 5.0%, a decrease of about 41%. For comparison, the rate of death during the first year of life among all babies in the general population declined from 1.5% during 1979-1983 to 0.9% during 1999-2003, a decrease of about 40%.
   
5. Having a child with Down syndrome has some surprising effects on the family. Mothers of individuals with Down syndrome typically exhibit better psychological well-being profiles in comparison to mothers of individuals with other intellectual and developmental disabilities. There is extensive evidence that mothers of young children with Down syndrome experience lower levels of stress, more extensive and satisfying networks of social support, less pessimism about their children’s future, and they perceive their children to have less difficult temperaments. A major study also found that divorce rates were lower (7.6%) for families of children with Down syndrome as compared to 10.8% in the population group with nondisabled children and 11.25% for families of children with other congenital birth defects. 

A study conducted in 2011 interviewed 282 siblings of people with Down syndrome. The respondents mentioned a variety of life lessons learned by having a sibling with Down syndrome, According to the study, “The most frequently cited lesson was an enhanced perspective on life — that life was good in many ways . . . These older brothers and sisters mentioned that they gained a deeper understanding and appreciation for human differences.” The vast majority of brothers and sisters describe their relationship with their sibling with Down syndrome as positive and enriching.