ABOUT DOWN SYNDROME
Down syndrome occurs in one out of every 733 live births, and more than 350,000 people in the U.S. have this genetic condition. One of the most frequently occurring chromosomal abnormalities, Down syndrome affects people of all ages, races and economic levels. Today, individuals with Down syndrome are active participants in the educational, vocational, social and recreational aspects of our communities. In fact, there are more opportunities than ever before for individuals with Down syndrome to develop their abilities, discover their talents and realize their dreams. For example, more teens and adults with Down syndrome each year are graduating from high school, going to college, finding employment and living independently.
The opportunities currently available to individuals with Down syndrome have never been greater. However, it is only through the collective efforts of parents, professionals, and concerned citizens that acceptance is becoming even more widespread. It is the mission of the National Down Syndrome Society to ensure that all people with Down syndrome are provided the opportunity to achieve their full potential in all aspects of their lives.
What is Down syndrome (Standard Trisomy 21)?
Down syndrome is the most commonly occurring chromosomal abnormality, resulting when an individual possesses three, rather than the usual two, copies of the 21st chromosome. This excess genetic material affects a person’s physical and cognitive development. People with Down syndrome will have some degree of mental retardation, usually in the mild to moderate range. There are many characteristics associated with Down syndrome, including low muscle tone, a flat facial profile, and an increased risk of some related medical conditions. However, every person with Down syndrome is a unique individual and may possess these characteristics to different degrees or not at all. In addition, all of these characteristics are found in the general population.
What is Translocation Down Syndrome?
Translocation is caused when a piece of chromosome 21 is located on another chromosome such as chromosome 14. The person with Translocation Trisomy 21 will have 46 chromosomes but will have the genetic material of 47 chromosomes. The person with Translocation Trisomy 21 will exhibit all the same characteristics of a person with Standard Trisomy 21 since they have three copies of chromosome 21. Translocation occurs between 3% and 5% of cases of Down syndrome.
What is Mosaic Down Syndrome?
Mosaic Down syndrome happens when a person has a percentage of cells that have three rather than two copies of the 21st chromosome and the remaining cells are unaffected. This type of Down syndrome accounts for about 2%-4% of the cases of Down syndrome.
Mosaic translocation Down syndrome occurs when a person has a percentage of translocation Down syndrome cells and the remaining cells are unaffected. Translocation happens when a piece of chromosome 21 becomes attached to another chromosome, during cell division. Translocation can be inherited by parents, but this is not always the case. This type of Down syndrome has not yet been studied, so we are unable to give an accurate number of occurrences.
According to research approximately 100-200 babies are born each year in America with mosaic Down syndrome. Due to lack of extensive international research, we are unable to confirm numbers for other countries but can assume that these numbers are similar in each country.
Because people with MDS often do not present the strong physical characteristics or delays present in Down syndrome, many live their lives without ever knowing they have this condition. In 2006, approximately 14,000 people in America have the diagnosis of MDS.
What impact does Down syndrome have on society?
Individuals with Down syndrome are becoming increasingly included in society and community organizations, such as school, health care systems, work forces, and social and recreational activities. Due to advances in medical technology, individuals with Down syndrome are living longer than ever before. In 1910, children with Down syndrome were expected to survive to age 9. With the discovery of antibiotics, the average survival age increased to 19 to 20. Now, with recent advancements in clinical treatment, as many as 80 percent of adults with Down syndrome reach age 55, and many live even longer. In the United States, Down syndrome affects approximately 350,000 families. Approximately 5,000 children with Down syndrome are born each year. As the mortality rate associated with Down syndrome is decreasing, the prevalence of individuals with Down syndrome in our society will increase. More and more Americans will interact with individuals with this genetic condition, increasing the need for widespread public education and acceptance.
Is Down syndrome hereditary?
The additional genetic material that causes Down syndrome can originate from either the father or the mother. Approximately 5 percent of the cases have been traced to the father. In general, the chance of having a second child with Down syndrome is about one in 100. The chance is greater if one parent carries a translocated cell, which can be determined through genetic testing. Down syndrome does not otherwise run in families and a sibling, aunt or uncle is at no greater risk of conceiving a child with Down syndrome.
Who is at risk of having a child with Down syndrome?
Women age 35 and older have a significantly increased risk of having a child with Down syndrome. A 35 year old woman has a one in 350 chance of conceiving a child with Down syndrome, and this chance increases gradually to one in 100 by age 40. At age 45, the incidence becomes approximately one in 30. However, because younger women in general give birth more frequently, most babies with Down syndrome are born to younger mothers. Genetic counseling for parents is becoming increasingly important. Still, many physicians are not fully informed about advising their patients about the incidence of Down syndrome, advancements in diagnosis, and the protocols for care and treatment of babies born with Down syndrome.
Why is it important to raise children with Down syndrome at home?
A greater understanding of Down syndrome and advancements in treatment of Down syndrome-related health problems have allowed people with Down syndrome to enjoy fuller and more active lives. Children raised at home and included in all aspects of community life can best reach their potential and function in society with a greater degree of independence. Parental love, nurturing, and support, as well as early intervention programs, educational opportunities, and community involvement, have a direct relationship to the degree that a person with Down syndrome is able to achieve his/her potential.
Why hasn’t Down syndrome received much attention in the past?
Even though Dr. Jerome Lejeune discovered in 1959 that it was an extra 21st chromosome that caused Down syndrome, it is only in the last few years that a focus has been placed on the study of the 21st chromosome. Why? Because we now have the technology to isolate specific genes and genetic material. The momentum is increasing. In May of 2000, an international team of scientists successfully identified and catalogued each of the approximately 225 genes on Chromosome 21. Researchers continue to look for the genes related to the development of the brain and the physical characteristics associated with Down syndrome. Once identified, it is hoped that the biochemical process that causes Down syndrome can be decoded, leading to the development of an intervention and therapy.
Down Syndrome: Myths and Truths
Myth: Down syndrome is a rare genetic disorder.
Truth: Down syndrome is the most commonly occurring genetic condition. One in every 733 live births is a child with Down syndrome, representing approximately 5,000 births per year in the United States alone. Today, Down syndrome affects more than 350,000 people in the United States.
Myth: Most children with Down syndrome are born to older parents.
Truth: Eighty percent of children born with Down syndrome are born to women younger than 35 years old. However, as a woman ages, her chance of conceiving a child with Down syndrome becomes greater.
Myth: People with Down syndrome are severely retarded.
Truth: Most people with Down syndrome have IQ’s that fall in the mild to moderate range of mental retardation. Children with Down syndrome are definitely educable, and educators and researchers are still discovering the full educational potential of people with Down syndrome.
Myth: Most people with Down syndrome are institutionalized.
Truth: Today people with Down syndrome live at home with their families and are active participants in the educational, vocational, social and recreational activities of the community. They are integrated into the regular education system, and take part in sports, camping, music, art programs, and all the other activities of their communities. In addition, they are socializing with people with and without disabilities, and as adults are obtaining employment and living in group homes and other independent housing arrangements.
Myth: Parents will not find community support in bringing up their child with Down syndrome.
Truth: In almost every community of the United States there are parent support groups and other community organizations directly involved in providing services to families of individuals with Down syndrome.
Myth: Children with Down syndrome must be placed in segregated special education programs.
Truth: Children with Down syndrome have been included in typical academic classrooms in schools across the country. In some instances they are integrated into specific courses, while in other situations students are fully included in the regular classroom for all subjects. The degree of mainstreaming is based on the abilities of the individual; but the trend is for full inclusion in the social and educational life of the community.
Myth: Adults with Down syndrome are unemployable.
Truth: Businesses are seeking young adults with Down syndrome for a variety of positions. They are being employed in small and medium sized offices: by banks, corporations, nursing homes, hotels and restaurants. They work in the music and entertainment industry, in clerical positions, and in the computer industry. People with Down syndrome bring to their jobs enthusiasm, reliability and dedication.
Myth: People with Down syndrome are always happy.
Truth: People with Down syndrome have a wide range of feelings just like everyone else. They respond to positive expressions of friendship, and they are hurt and upset by inconsiderate behavior.
Myth: Adults with Down syndrome are unable to form relationships leading to marriage.
Truth: People with Down syndrome date, socialize and form on-going relationships. Some get married. Women with Down syndrome can and do have children, and there is a 50 percent chance that their child will have Down syndrome. Although rare, men with Down syndrome can father children.
Myth: Down syndrome is untreatable.
Truth: Through early intervention, speech therapy, physical therapy and occupational therapy, it is possible to improve many of the problems associated with Down syndrome. In addition, research on Down syndrome is making great strides in identifying the genes on chromosome 21 that cause Down syndrome. Scientists now feel strongly that it will be possible to improve, correct, or prevent many of the problems associated with Down syndrome in the future.