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Down Syndrome

Down Syndrome. Sayed Zeeshan Alvi Premed 3. What is it?. Down syndrome, also known as Trisomy 21, is a genetic disorder that presents complications in a persons physical and mental capabilities. History. During ancient times, infants with disabilities were either abandoned or killed.

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Down Syndrome

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  1. Down Syndrome • Sayed Zeeshan Alvi • Premed 3

  2. What is it? • Down syndrome, also known as Trisomy 21, is a genetic disorder that presents complications in a persons physical and mental capabilities.

  3. History • During ancient times, infants with disabilities were either abandoned or killed. • Doctor John Langdon Down was the first to describe the characteristics of Down syndrome in a published report in 1866. • By the 20th century, Down syndrome was formally recognized as a mental disability.

  4. Causes

  5. Genetics • Trisomy 21 • Translocation

  6. Trisomy 21 • AKA 47,XX,+21 for females and 47,XY,+21 for males • caused by a failure of the 21st chromosome to separate during gamete formation. • Results in having an extra chromosome present in either egg or sperm(24 chromosomes). • Final zygote has 47 chromosomes, 3 being chromosome 21, thus Trisomy 21 • 88% of cases of trisomy 21 result from non separation of the chromosomes in the mother, 8% from non-separation in the father, and 3% after the egg and sperm have merged • In mosaic Down syndrome 1 to 2.5% of cases, some of the cells in the body are normal and others have trisomy 21

  7. Translocation • Extra chromosome 21 occurs due to a Robertsonian translocation (2–4% chance). • The long arm of chromosome 21 is attached to another chromosome, often chromosome 14. • Can occur as a new mutation or hereditary

  8. Signs

  9. Complications • Heart: congenital heart disease in newborns with Down syndrome is around 40%. • Hearing and Vision:Vision problems occur in 38 to 80%. Between 20 and 50% have strabismus, in which the two eyes do not move together. Cataracts occur in 15%, and may be present at birth. • Neurological: Individuals with Down syndrome have mild (IQ: 50–70) or moderate (IQ: 35–50) intellectual disability with some cases having severe (IQ: 20–35) difficulties. • Fertility: Males with Down syndrome usually do not father children, females have lower rates of fertility relative those who are unaffected. Fertility is estimated to be present in 30–50% of women.

  10. Epidemiology • Down syndrome occurs in about 1 per 1000 births and results in about 17,000 deaths. • Maternal age affects the chances of having a pregnancy with Down syndrome. At age 20 the chance is 1 in 1441; at age 30 it is 1 in 959; at age 40 it is 1 in 84; and at age 50 it is 1 in 44

  11. Management • Screen for Diseases • Hearing Aid • Speech Therapy • Sign Language • Monitor heart (electrocardiogram and ultrasound of the heart) • Physical Therapy • Tonsillectomy(prevent sleep apnea)

  12. Sources • http://en.wikipedia.org/wiki/Down_syndrome • http://www.ndss.org/ • http://www.gizmodo.com.au/2013/07/scientists-may-have-found-a-genomic-off-switch-for-downs-syndrome/ • http://www.larasig.com/sites/larasig.com/files/images/trisomy21_0.jpg

  13. Thank You

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