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