How to Get Rid of Down's Syndrome
Information of Down's Syndrome
In 1866, Langdon Down tried to relate the appearance of certain groups of patients to the physical features of ethnic groups. One of his groups had the condition originally called mongolism, and now generally known as Down's syndrome. This condition is a frequent cause of learning disability, occurring in 1 in every 650 live births. It is more frequent among older women, occurring in about 1 in 2000 live births for mothers aged 20-25 and 1 in 30 for those aged 45. The incidence of Down's syndrome has decreased because of reduced birth rates a1lJ.ong older women, and increases in detection of the condition by amniocentesis and subsequent termination of pregnancy. Usually the learning disability is mild or moderate, but occasionally it is severe.
Cause of Down's Syndrome
In 1959, Down's syndrome was found to be associated with the chromosomal disorder of trisomy (three chromosomes instead of the usual two). About 95% of cases are due to trisomy 21. These cases result from failure of disjunction during meiosis and are associated with increasing maternal age. The risk of recurrence in a subsequent child is about 1 in 100. The remaining 5% of cases of Down's syndrome are attributable either to translocation involving chromosome 21 or to mosaicism. The disorder leading to translocation is often inherited, and the risk of recurrence is about 1 in 10. Mosaicism occurs when non-disjunction takes place during any cell division after fertilization. Normal and trisomic cells occur in the same person, and the effects on cognitive development are particularly variable (Thapar et at. 1994). Down's pathology is presumed to be due to the increased 'dosage' of genes on chromosome 21. This could account for the excess of early-onset Alzheimer's.
Symptoms of Down's Syndrome
The clinical picture is made up of a number of features, anyone of which can occur in a normal person. Four of these features together are generally accepted as strong evidence for the syndrome. The most characteristic signs are:
- a small mouth and teeth, furrowed tongue, and high-arched palate;
- oblique palpebral fissures and epicanthic folds;
- flat occiput;
- short and broad hands, a curved fifth finger and a single transverse palmar crease; and
- hyperextensibility or hyperflexibility of joints and hypotonia.
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