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Presentation on theme: "Chromosomes."— Presentation transcript:

1 Chromosomes

2 Chromosome Abnormalities
Numerical abnormalities Structural abnormalities Mixoploidy

3 Numerical Abnormalities
Monosomy Trisomy

4 A. B. C.

5 Non-disjunction

6 Consequence of non-disjunction
Trisomy (21) Down syndrome (13) Patau syndrome (18) Edward’s syndrome

7 Polyploidy Addition of one or more entire set of chromosomes

8 Disorders of Chromosome Number
Down Syndrome Patau and Edwards Syndrome Klinefelter Syndrome Turner Syndrome XXX Females and XYY Males

9 Down Syndrome

10 Down Syndrome History Incidence 1 in 691 births in the US
1866 first clinically described by Dr. Down 1959 chromosomal basis discovered Incidence 1 in 691 births in the US Majority of cases are diagnosed prenatally (~60%) Prevalence: currently 400,000 in US


12 Patau Syndrome

13 Patau Syndrome Heart defects Brain or spinal cord abnormalities
Weak muscle tone Prognosis 45% die within few days/weeks 80% within 1st year

14 Edwards Syndromes

15 Edward’s syndrome Clinical symptoms Structural heart defects
Intestinal abnormalities Breathing difficulties Intellectual disability Prognosis Median lifespan – 5-15 days Longer than 1 year – 8% Live to 10 years- 1%

16 Klinefelter Syndrome

17 Klinefelter Syndrome (XXY)
Incidence- 1 in 1000 live male births Clinical features- Lower than normal verbal IQ Infertility Testosterone treatment

18 Turner’s Syndrome

19 Turner Syndrome (X) Incidence- 1 in 5000 – 10,000 female births
Clinical features Loss of ovarian function Normal intelligence Developmental delay Learning disability Estrogen treatment from puberty on

20 https://www. youtube. com/results

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