What Is Down Syndrome ?

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Down Syndrome Awareness Starts With Knowledge

Learn The Basics Of What Down Syndrome Is.

Down syndrome is a genetic condition where an individual has three, rather than two, copies of chromosome 21. Down syndrome is the most frequently occurring chromosomal abnormality and effects one in every 691 babies born in the United States. The disorder was first identified in 1866 by John Langdon Down, a British physician, and later named after him. Today, there are more than 250,000 people living with Down syndrome in the United States.

Children who are born with Down syndrome have an increased risk for certain medical conditions such as congenital heart defects, thyroid conditions, airway and respiratory problems, vision and hearing problems, and occasionally childhood leukemia (1%). These children will also experience mild to moderate cognitive delays.

Quality educational programs, a stimulating home environment, appropriate therapies, good health care and positive support from family, friends and the community enable people with Down syndrome to develop their full potential and lead fulfilling lives.

It is named after John Langdon Down, the British physician who described the syndrome for the first time in 1866.

Down syndrome, also called Down’s syndrome, trisomy 21, or (formerly) mongolism, congenital disorder caused by the presence in the human genome of extra genetic material from chromosome 21.

Down syndrome occurs because of the extra copy of chromosome 21, which can cause the body and brain to develop differently than a child without the syndrome. Researchers have extensively studied the defects in chromosome 21 that cause Down syndrome.

In 88% of cases, the extra copy of chromosome 21 is derived from the mother. In 8% of the cases, the father provided the extra copy of chromosome 21. In the remaining 2%, Down syndrome is due to what is perceived as mitotic changes, a variation in cell division which occurs after fertilization when the sperm and ovum are joined.

Down syndrome is the most common chromosomal condition. It’s also the leading worldwide cause of intellectual and developmental delays in children. In the United States, approximately 6,000 babies are born with Down syndrome every year.

There are three types of Down syndrome. Each type impacts the body’s chromosomes. Chromosomes contain the genetic information that tells our body how to grow.

  • Trisomy 21, or nondisjunction, accounts for 95% of Down syndrome cases. It happens when an extra copy of chromosome 21 is present in all cells of the body.
  • Translocation Down syndrome impacts about 4% of affected babies. It is the only type of Down syndrome that can be inherited from a parent. The baby will have three copies of chromosome 21, but one attaches to another chromosome. In trisomy 21, the extra copy is separate. To assess risk, parents can consult with a genetic counselor or geneticist.
  • Mosaic Down syndrome accounts for about 1% of Down syndrome cases. It happens when an extra copy of chromosome 21 is present in some, but not all, of the body’s cells. This type of Down syndrome results from a random event shortly after the egg and sperm join together. When cells are dividing, some cells receive an extra copy of chromosome 21. Other cells have two copies.

Yes, Down syndrome is a genetic disorder. Abnormal cell division leads to an extra full or partial copy of chromosome 21. The extra genetic material can cause various medical and developmental issues.

In most cases, Down syndrome is not an inherited condition. It develops because of an error during fetal cell division.

But, it is possible for a child to inherit translocation Down syndrome. This occurs when a parent’s chromosomes have rearranged genetic material.

ABSOLUTELY NOT! Children who are born with down syndrome are just as special and unique as any other children. 

Down syndrome is most often noticed at birth or shortly thereafter. Physical characteristics alone aren’t enough for a diagnosis, though. Chromosome testing will confirm concerns and provide a firm diagnosis.


Physical characteristics alone are not a diagnosis of Down syndrome. But, children with Down syndrome often share physical similarities. These traits include low muscle tone, small stature and upward slanting eyes. A single deep crease across the palm and wide, short hands with short fingers are also common.

A baby’s physical features do not mean they have Down syndrome. Physicians use chromosome testing to make a diagnosis.

It is important to remember that every child with Down syndrome is a unique individual. Children may have these physical characteristics to different degrees, or not at all.

Children with Down syndrome have an increased risk for certain medical conditions. They include congenital heart defects, respiratory problems, hearing/vision problems and thyroid conditions.

Many of these conditions are successfully managed with medication and expert medical care. At Children’s Colorado, our physician, nurse practitioner and other specialists help families.

A wide range of cognitive delays are also common in Down syndrome. Developmental intervention is crucial. Appropriate school placement and accommodations to help each child learn are also important. This maximizes the child’s innate strengths and talents.

The average life expectancy for a child with Down syndrome has increased dramatically. In the 1920s, the average life span for a child was nine years. Now, the average life expectancy is approximately 60 years.

Quality of life for people with Down syndrome has also improved. Early medical care and developmental intervention are crucial. With support, people with Down syndrome live rich lives full of meaningful experiences. Some adults even develop the skills to live on their own and maintain a job.

To lead fulfilling and productive lives, people with Down syndrome need certain things. Good healthcare, quality educational programs and a stimulating home environment are vital. Loving support from family, friends and the community are also important. Each factor will help a person with Down syndrome lead a fulfilling and productive life.

Always speak directly with the person with Down syndrome, not the person with them. Give them time to respond. Take their lead on what support they need to communicate. Know that every person with Down syndrome is unique, with their individual personality, strengths and support needs.

For persons with Down’s Syndrome, communicating with them may pose certain challenges. However, if effort is made, quality interactions with them are possible. Here are a few tips on how to do that.

  • Talk About Day-to-Day Activities
    Make use of your daily activities as talking points. This helps them to recognize and associate words and ideas with actual experiences they went through. For instance, you can ask about whether they liked their food or not.
  • Use Visual Cues
    Communicate with them using visual gestures and signs. These cues reinforce communication abilities especially if they are still learning about some words. You can do hand signals or facial expressions to emphasize your point.
  • Copy the Person’s Response
    Observe the person’s response and copy their expressions. Smile if they smile, shrug if they shrug, but let them be when they’re not in the mood. We have seen that reflecting their responses makes them more interactive.
  • Be Animated in Interacting
    Along with copying their expressions, it also helps if you are animated when you talk to them. This gets them hooked to pay attention to you and observe your mouth as you speak. Consequently, this improves their understanding of new vocabularies.
  • Use Repetition
    It is also very helpful to repeat words and ideas to them. For instance, if they point to a dog but they only get to pronounce “d” or “g”, repeat this for them with emphasis on pronouncing “dog”. If they also point at something that they incorrectly address, you can repeat to them the correct word.
  • Show You Are Pleased
    A person with Down’s Syndrome is also encouraged to interact more when the person they’re talking to is pleased with them. Smile and be cheerful when talking to them. We have seen this work.
  • Stay Physically Close
    When interacting with a person with Down’s Syndrome, it’s very helpful to be physically close. They will not only sense your comforting presence, but they can also clearly hear you and observe the way you use words.
  • Be Patient
    Patience is also very necessary when communicating with persons with Down’s Syndrome. They may take time to respond to your message or you may need to speak slower than you usually do. However, know that your patience will be rewarded with productive communication.

Absolutely! People with Down syndrome can live fulfilling and independent lives. They attend school, pursue higher education, and excel in various careers, from the arts to business and beyond. They participate in sports, build friendships, and enjoy hobbies just like anyone else. With the right support, individuals with Down syndrome can achieve their goals and contribute meaningfully to their communities.

Many people with Down syndrome thrive in inclusive environments that recognize their unique strengths and potential. It’s important to focus on abilities, not limitations.

People with Down syndrome should always be referred to as people first. Avoid: “a Down syndrome child” or “Down’s child” – it should be “a child with Down syndrome.” describing the condition as “Down’s,” as in, “He has Down’s.”

There’s no cure for Down syndrome, but treatment is available to help your child reach their full potential. Treatment focuses on helping your child thrive physically and mentally. Treatment options could include: Physical or occupational therapy

Treatment Therapies Include
  • Physical therapy includes activities and exercises that help build motor skills, increase muscle strength, and improve posture and balance. …
  • Speech-language therapy can help children with Down syndrome improve their communication skills and use language more effectively.