In 1866 the physical characteristics of people with Down Syndrome were linked with decreased intellectual ability and grouped as one syndrome. The English physician, John Langdon Down, was the first to publish these findings.
Due to the fact that the facial features of people with Down Syndrome were similar to those of people from Mongolia, he used the term mongoloid to refer to a person with (what is now known as) Down Syndrome.
It was not until 1959 that Dr. Jerome Lejeune, a French physician, made the discovery that Down Syndrome was the result of a chromosomal abnormality. His research led him to the fact that the cells of people with Down Syndrome (mongoloids, at the time) had 47 chromosomes, whereas the cells of people without the syndrome only had 46 chromosomes.
Just a little while after that, it was discovered that chromosome number 21 contained an extra partial or complete chromosome in these so called “mongoloids”. Thus, the term Trisomy 21 was born. Mongoloid is now considered to be a pejorative term and should be avoided when referencing a person with Down syndrome.
In the vast majority of cases, Down Syndrome is not hereditary – meaning it is no one’s fault if a baby has the condition
As yet we do not know what causes the presence of an extra chromosome 21. It can come from either the mother or the father, but most commonly from the mother. There is no way of predicting whether a parent is more likely to produce an egg or sperm with 24 chromosomes. There is a definite link with advanced maternal age for reasons yet unknown. However, most babies with Down syndrome are born to women under the age of 35, as younger women have higher fertility rates.
For every 800 babies born, one will have Down syndrome. Down syndrome affects people of all ages, races, religious backgrounds and economic situations. Nothing done before or during pregnancy can cause Down syndrome. It occurs in all races, social classes and in all countries throughout the world. It can happen to anyone.
The diagnosis of Down syndrome is usually made soon after the birth of the baby because of the baby’s appearance. There are many physical characteristics associated with the condition, which may lead a parent or midwife, or other medical professional, to suspect that the baby has Down syndrome. As pre-natal testing has become more prevalent, many women are now able to get tested during their first trimester
- Reduced muscle tone which results in hypotonia
- A flat facial profile, flat nasal bridge, small nose
- Eyes that slant upwards and outwards, often with a fold of skin that runs vertically between the lids at the inner corner of the eye (epicanthic fold)
- A small mouth which makes the tongue seem slightly large
- A big space between the first and second toe (sandal gap)
- Broad hands with short fingers and a little finger that curves inwards. The palm may have only one crease across it (single palmar crease)
- A below average birth weight and length at birth
It is not uncommon for these features to also occur in the general population. Therefore a chromosome test (karyotype) needs to be performed before a positive diagnosis could be made.
There are certain health problems that are more common in people with Down syndrome than in the rest of the population. These include:
- 40-50% of babies with Down syndrome are born with heart problems, many of which require heart surgery
- A significant number of people with Down syndrome will have hearing and sight problems
- Thyroid disorder
- Poor immune system
- Respiratory problems, coughs and colds
- Obstructed gastrointestinal tract
However, with advances and increased access to medical care most of these problems are treatable. None of these problems is unique to people with Down syndrome – they also occur in the rest of the population.
It is also important to remember that some people with Down syndrome do not experience any health problems.Â Advances in treatments and increased access to medical care have also meant that people with Down syndrome are living much longer. Life expectancy is now put at 60-65, and many people with Down syndrome live even longer.
All people with Down syndrome will have some degree of intellectual disability. Children with Down syndrome do learn to walk, talk and be toilet trained but in general will meet these developmental milestones later than their typical peers. There is a wide variation in ability in people with Down syndrome just as there is in the rest of the population.Â Early intervention programs help in all areas of child development are now widespread. These programs can include speech and physical therapy as well as home teaching programs for the child and the family.
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- What is the cause of the Down syndrome disorder (wiki.answers.com)