Презентация на тему Down syndrome

as trisomy 21, is a genetic disorder caused by

the presence of all or part of a third copy of chromosome 21. Trisomy 21 is the most common chromosome abnormality in humans.It is typically associated with a delay in cognitive ability (mental retardation, or MR) and physical growth, and a particular set of facial characteristics. The average IQ of young adults with Down syndrome is around 50, whereas young adults without the condition typically have an IQ of 100.(MR has historically been defined as an IQ below 70.) A large proportion of individuals with Down syndrome have a severe degree of intellectual disability.
Down syndrome is named after John Langdon Down, the British physician who described the syndrome in 1866. The condition was clinically described earlier by Jean Etienne Dominique Esquirol in 1838 and Edouard Seguin in 1844. Down syndrome was identified as a chromosome 21 trisomy by Dr. Jérôme Lejeune in 1959. Down syndrome can be identified in a baby at birth or before birth by prenatal screening. Pregnancies with this diagnosis are often terminated.
The CDC estimates that about one of every 691 babies born in the United States each year is born with Down syndrome.
Many children with Down syndrome are educated in regular school classes while others require specialised educational facilities. Some children graduate from high school,and, in the US, there are increasing opportunities for participating in post-secondary education. Education and proper care has been shown to improve quality of life significantly. Many adults with Down Syndrome are able to work at paid employment in the community, while others require a more sheltered work environment.

What is it?

Answer

characterized by the neotenization of the brain and body.

Down syndrome is characterized by decelerated maturation (neoteny), incomplete morphogenesis (vestigia) and atavisms. Individuals with Down syndrome may have some or all of the following physical characteristics: microgenia (abnormally small chin), oblique eye fissures on the inner corner of the eyes,muscle hypotonia (poor muscle tone), a flat nasal bridge, a single palmar fold, a protruding tongue (due to small oral cavity, and an enlarged tongue near the tonsils) or macroglossia, "face is flat and broad", a short neck, white spots on the iris known as Brushfield spots, excessive joint laxity including atlanto-axial instability, excessive space between large toe and second toe, a single flexion furrow of the fifth finger, a higher number of ulnar loop dermatoglyphs and short fingers.
Growth parameters such as height, weight, and head circumference are smaller in children with DS than with typical individuals of the same age. Adults with DS tend to have short stature and bowed legs—the average height for men is 5 feet 1 inch (154 cm) and for women is 4 feet 9 inches (144 cm). Individuals with DS are also at increased risk for obesity as they age.