What is Down syndrome?

March is Developmental Disabilities Awareness Month and, this week, the staff at NARIC would like to highlight Down syndrome. The Mayo Clinic defines Down syndrome as a genetic disorder that is “caused when abnormal cell division results in extra genetic material from chromosome 21.” Down syndrome varies in severity and causes lifelong intellectual disability and developmental delays. In some people, Down syndrome can cause additional health problems, such as gastrointestinal blockage, psoriasis, ear infections, hearing loss, and poor vision.

The extra genetic material from chromosome 21 that results from cell division abnormalities is responsible for the features and developmental problems of Down syndrome. There are three genetic variations that can cause Down syndrome:

  • Mosaic Down syndrome is a rare form of Down syndrome. Children with this type of Down syndrome have some cells with an extra copy of chromosome 21. Abnormal cell division after fertilization causes this mosaic of normal and abnormal cells.
  • Translocation Down syndrome occurs when a part of chromosome 21 is translocated or attached onto another chromosome before or during conception. People with this type of Down syndrome have the usual two copies of chromosome 21; however, the additional material from chromosome 21 is also attached to the other chromosome. Translocation Down syndrome is the only form of Down syndrome that can be inherited, but only 4 percent of children with Down syndrome have this form of the disorder.
  • Trisomy 21 causes Down syndrome about 95 percent of the time. In this case, people with Trisomy 21 have three copies of chromosome instead of the usual two copies in all cells. Abnormal cell division during the development of the sperm cell or egg cell causes this.

Currently, there are no known behavioral or environmental factors that cause this disorder. And aside, from Translocation Down syndrome, it is not inherited. However, some parents have a greater chance of having a child with Down syndrome. Factors include advancing maternal age, already having a child with Down syndrome, and if the parents are carriers of Translocation Down syndrome.

Recommended by the American College of Obstetricians and Gynecologists regardless of the age of the expecting mother, screening tests can indicate the likelihood a mother is carrying a baby with Down syndrome and diagnostic tests can identify if your baby has Down syndrome. If you are pregnant, talk with your doctor(s) about the types of tests, their advantages and disadvantages, their benefits and risks, and what the results mean. It is possible that your doctor may recommend that you speak with a genetics counselor. Visit the Mayo Clinic’s page on these screening and diagnostic tests to learn more.

A child with Down syndrome can have a variety of secondary conditions related to Down syndrome. These conditions become more prominent as they age. These conditions can include heart defects, leukemia, and infectious diseases due to abnormalities in their immune systems, dementia, sleep apnea, obesity, and other problems. To learn more about these conditions visit the Mayo Clinic’s page on complications related to Down syndrome. On the other side, the life span for people with Down syndrome has increased exponentially. For example, a baby born with Down syndrome in 1910 did not usually live to the age of 10. A little over a century later, people with Down syndrome can expect to live beyond the age of 60, depending on the severity of health problems or secondary conditions.

Early intervention programs play a major role for infants and children with Down syndrome. These programs usually involve therapists and special educators, whose goal is to help your child develop language, social and motor skills, and self-help skills. They help them realize their potential abilities and they can make a difference in the children’s quality of life. Early intervention programs are available in most states and the types and duration of the programs may vary. Currently, NIDILRR is funding a project on an intervention that promotes goal-directed behavior in infants with Down syndrome.

As a new or expectant parent or grandparent, you may experience a range of emotions when you learn that your child or grandchild has Down syndrome. There are several steps you can take to prepare yourself and find the information and support you need to take care of your child. These steps include finding a team of trusted professionals, including healthcare providers and teachers, who can help you evaluate the resources in your area and who can explain state and federal programs for children with disabilities; seeking out other families who are dealing with the same issues, your community may have support groups for parents of children with down syndrome; and expecting a bright future since most people with Down syndrome can live fulfilling lives with their families or independently, attend mainstream schools, and have jobs.

The NIDILRR community has been doing research on Down syndrome and related areas for many years. We conducted a search of our collection of NIDILRR grantee publications and found over 40 years’ worth of research! Here are just a few of those articles:

  • Profiles of everyday executive function in young children with Down syndrome. (J69049).
  • School function in students with Down syndrome. (J69048).
  • “I have a good life”: The meaning of well-being from the perspective of young adults with Down syndrome. (J69392).

There are a lot of resources available for people with Down syndrome and their families. Here are just a few of them:

  • The Center for Parent Information and Resources provides information in English and Spanish to parents of children with Down syndrome that includes information on education, health considerations, information for high school students with Down syndrome, a list of organizations, and tips for parents and teachers.
  • The National Association for Down Syndrome includes information for expecting parents and information for parents of infants and toddlers, children, and teens and adults with Down syndrome.
  • The Global Down Syndrome Foundation provides information about Down syndrome, research, and medical care. They also provide a list by state of known Down syndrome organizations.

If you would like to find resources in your area, please feel free to contact NARIC’s information specialists by calling 800/346-2742 or emailing NARICInfo@heitechservices.com.

About mpgarcia

I'm the Bilingual Information/Media Specialist at NARIC.
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One Response to What is Down syndrome?

  1. Pingback: What are Patau Syndrome and Edward Syndrome? | Collection Spotlight from the National Rehabilitation Information Center

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