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e-mail: pam@theupsofdowns.com
Research
I visit a website www.dsrf.co.uk for updates on research etc. I think it is one of the best sites around and is regularly updated : Download the latest newsletter here.I have commented before on my personal worries about companies selling concoctions of drugs for our children without all the research being finalised, but the dsrf have been completing there studies and I await there results with anticipation, if these vitamins and antioxidents can make a difference and have no detrimental affects then obviously I would let my little Katy take them too. The site is well worth a visit.
WHAT CAUSES DOWN SYNDROME?
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Down's Syndrome is a set of special characteristics produced by extra chromosome 21 material. In 90-95% of all cases this is in the form of Standard Trisomy 21, in which every cell in the body will usually have an extra number 21 chromosome. In 2-5% of the cases a mixture of trisomic cells, containing the extra 21 chromosome, and normal cells are found. This is called Mosaic Trisomy 21. In another 2-5% of cases the extra chromosome 21 is attached to another chromosome and this is called Translocation Trisomy 21.
In all cases of Down's Syndrome the extra chromosome 21 is present in either the sperm or the egg before fertilisation takes place, or it arises in the first division of the fertilised egg. It is very important to understand that nothing that took place during the pregnancy was the cause.
The extrsa chromosome 21 is a normal healthy chromosome and a copy of either the mother or the fathers 21 chromosome. Thus the special physical and mental characteristics associated with Down's Syndrome arise from an imbalance in genetic material which disrupts the normal programme of development and growth.
The majority of cases of Down's Syndrome (about 90%) are not associated with a family tendancy towards having babies with this condition.
About one third of all translocation trisomies are inherited, either the father or the mother being a balanced carrier. Therefore about one in a hundred cases of Down's Syndrome is inherited. Parents whose infant has this form of chromosome abnormality should seek genetic counselling.
Down's Syndrome is found in all races of people, in all social and economic classes and in all countries. Trisomies have also been found in other species.No relationship between diet, illness, geographic area or climate and the occurance of the syndrome have been substantiated.
Some recent studies have shown that 20 to 25% of all cases the extra chromosome has come from the father.The one consistent relationship established is the increased risk of having a baby with Down's Syndrome as parents get older. The risk for mothers in their early twenties is about 1 in 2,000, at 35 it is 1 in 800, and then sharply rises to around 1 in 45 at 45 years old. |
DEVELOPMENT
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Nearly all children with Down's Syndrome can be expected to continue to develop and learn until late adolescence or early adulthood, and will contine to learn new skills and knowledge for most of their lives. The development is marked by periods of little apparent progress and periods of rapid progress. As a group,their IQ is fairly stable by two to three years of age, at least to late adolescence. If they are provided with good health care, emotional security and early education, the majority will fall into moderate or mild catagories of retardation. They can be expected to respond to educational experiences and make steady progress well into their twenties and possibly beyond.
We can expect the majority will attain self-help skills, sufficient language to communicate and converse, a range of interests, hobbies and activities. The majority will be able to live in the community, either at home, in sheltered communities or, in some cases, in their own accommodation.
There have always been some people with Down's Syndrome who show exceptional abilities and qualities. There are instances of people with the condition who have written books, acted in television plays, won art competions and achieved high levels in dance, scouting and music. There are those who live and work in the community. Some are married and have mature andcaring relationships. There have been people with Down's forming and joining in groups to discuss the needs of the disabled, and demanding the right to make decisions about their own lives. But whether or not they amaze us by their achievements, and this will depend on what we expect, far more will be able to lead happy, fulfilled and more independent lives than Langdon Down could ever have imagined when he first recognisrd and described the condition in 1866. |
What is Downs
Down syndrome (also called Down's syndrome) encompasses a number of genetic disorders, of which trisomy 21 (a nondisjunction) is the most representative, causing highly variable degrees of learning difficulties and physical disabilities. This genetic disorder was
named after John Langdon Haydon Down, the British doctor who described it.
Overview
Incidence of Down syndrome is estimated at 1 per 660 births and is the most common chromosomal abnormality. It is a commonly known observation that maternal age influences the risk of conceiving a baby with the syndrome. At age 20-24, it is only 1/1490, while at age 40 it is 1/106 and at age 49 it is 1/11. (Source: Hook EB. Rates of chromosomal abnormalities at different maternal ages. Obstet Gynecol 1981;58:282.)
Down syndrome is named after John Langdon Haydon Down, who first described the condition. The term was first used by the editor of The Lancet in 1961 [1] (http://www.intellectualdisability.info/values/history_DS.htm). It was originally called mongolism or mongolian idiocy, after a perceived resemblance observed by Down between the faces of some of his patients with Down syndrome and the mongoloid race. This usage, like other medical terms used at the time, has become a term of abuse, and is now generally viewed as both offensive and medically meaningless.
Trisomy 21 is the existence of a third copy of the chromosome 21 in cells throughout the body of an affected person. The condition puts children with Down syndrome at an immediate disadvantage compared with children who do not have DS. The IQ of a child with Down syndrome is rarely measured above 60. The brain of children with Down syndrome is usually small and underweight. The cerebellum and brain stem are unusually small. So is the superior temporal gyrus. Educational progress may also be damaged by illness and disabilities such as recurring infectious diseases, heart problems, eyesight, and hearing problems.
Early educational intervention, screening for common problems such as thyroid functioning, medical treatment where indicated, a conducive family environment, vocational training, etc. can produce excellent progress in the overall development of children with Down syndrome. On the one hand, Down syndrome shows that we cannot jump over genetic limitations; on the other, it shows that education can produce excellent progress whatever the starting point. The commitment of parents, teachers and therapists to individual children has produced previously unexpected positive results.
Medical research
Of the inborn disorders that affect intellectual capacity, Down syndrome is the most prevalent and best studied. Down syndrome is a term used to encompass a number of genetic disorders of which trisomy 21 is the most representative (95% of cases). Trisomy 21 is the existence of the third copy of the chromosome 21 in cells throughout the body of the affected person. Other Down syndrome disorders are based on the duplication of the same subset of genes (e.g., various translocations of chromosome 21). Depending on the actual etiology, the learning disability may range from mild to severe.
Trisomy 21 results in over-expression of genes located on chromosome 21. One of these is the superoxide dismutase gene. Some (but not all) studies have shown that the activity of the superoxide dismutase enzyme (SOD) is elevated in Down syndrome. SOD converts oxygen radicals to hydrogen peroxide and water. Oxygen radicals produced in cells can be damaging to cellular structures, hence the important role of SOD. However, the hypothesis says that once SOD activity increases disproportionately to enzymes responsible for removal of hydrogen peroxide (e.g., glutathione peroxidase), the cells will suffer from a peroxide damage. Some scientists believe that the treatment of Down syndrome neurons with free radical scavengers can substantially prevent neuronal degeneration. Oxidative damage to neurons results in rapid brain aging similar to that of Alzheimer's disease.
Another chromosome 21 gene that might predispose Down syndrome individuals to develop Alzheimer's pathology is the gene that encodes the precursor of the amyloid protein. Neurofibrillary tangles and amyloid plaques are commonly found in both Down syndrome and Alzheimer's individuals. Layer II of the entorhinal cortex and the subiculum, both critical for memory consolidation, are one of the first affected by the damage. A gradual decrease in the number of nerve cells throughout the cortex follows. A few years ago, Johns Hopkins scientists created a genetically engineered mouse called Ts65Dn (segmental trisomy 16 mouse) as an excellent model for studying the Down syndrome. Ts65Dn mouse has genes on chromosomes 16 that are very similar to the human chromosome 21 genes. With this animal model, the exact causes of Down syndrome neurological symptoms may soon be elucidated. Naturally, Ts65Dn research is also likely to highly benefit Alzheimer's research. Whilst there are a number of commercially promoted dietary supplements on the market, especially in the USA, mainly involving various combinations of vitamins and minerals, none of these have been medically approved for use in the UK for the mass-treatment of people with Down syndrome, none appear to lead to any proven lasting benefits, and they all remain highly controversial.
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