1. Chromosomal Disorders*
Chromosomal Disorders
Widespread genetic alterations, since entire chromosomes are modified – which means that thousands of genes are affected at once. *
= Required Notes

2. *
Vocab
Autosomes = All chromosomes except the sex chromosomes (# 1 through 22 in humans)
Sex Chromosomes = Chromosomes that determine gender (Pair # 23 in humans)
Nondisjunction = failure of chromosomes to separate during meiosis. This results in a gamete with either an extra or a missing chromosome.
Trisomy = Having 3 chromosomes instead of the usual pair.
Monosomy = Having 1 chromosome instead of the usual pair.
Karyotype = A picture of the chromosomes in a cell.

3. Nondisjunction (draw this!)*
Egg Cell Meiosis
Replication
Reduction Division
Trisomy after fertilization (3 chromosomes)
Nondisjunction (chromosomes fail to split!)
Monosomy after fertilization (only 1 chromosome)
Normal Ova
Normal Chromosome Pair after fertilization

4. *
Trisomy 21 Down Syndrome

5. * * * Statistics One in every 800 to 1000 live births
Over people in the U.S have the disorder
The average mental age achieved is 8 years old
Each year 5000 children in the US are born with the disorder
The likelihood of having a child with Down’s Syndrome increases dramatically when the mother is over 40 years old * * *

6. Phenotype Physical Characteristics*
Phenotype Physical Characteristics
Flat facial profile: small nose
Upward slant to the eyes
Small mouth
Hyperflexibility
Enlargement of tongue
Broad short hands

7. * Complications Hearing loss Vision problems Cardiac Abnormalities
Increased susceptibility to infections

8. Down’s Syndrome Karyotype
What can you tell from this photo of chromosomes?
Trisomy 21!!
Male!!

9. Phenotype

10. Phenotype (cont.)

11. Trisomy 18 Edwards Syndrome

12. Statistics Occurs in 1 in 8000 births
Most die in embryonic or fetal life
2nd most common autosomal aberration

13. Phenotype Physical Characteristics
Webbed features
Cleft lip +/- palate
Microcephaly with prominent occiput (“small head which bulges in back”)
Fixed flexion deformity of the fingers (overlapping of the 2nd and 5th fingers over the 3rd and 4th fingers)

14. Complications
Complications depend on the specific abnormalities that affect the infant.

15. Edward’s Syndrome Karyotype
Boy or Girl?

16. Phenotype

17. Trisomy 13 Patau’s Syndrome

18. Statistics Occurs in 1 in 20000 live births
Almost half of the affected infants do not survive beyond the first month and about three quarters die within six months.

19. Phenotype Physical Characteristics
Small head (Microcephaly)
Small eyes (microphthalmia)
Cleft lip
Cleft palate
Eyes close set (hypotelorism); eyes may actually fuse together into one

20. Complications Breathing difficulty Deafness Vision Problems
Feeding problems
Seizures
Heart failures

21. Patau’s Syndrome Karyotype
Boy or Girl?

22. Phenotype

23. Phenotype (cont.)

24. Cri-du-chat
Syndrome
(Cat Cry Syndrome)

25. Statistics Most common human deletion syndrome
Segment of chromosome 5 is missing (an autosomal disorder)
Effects 1 in 20,000 to 50,000 births

26. Phenotype Physical Characteristics
Low birth weight
Small head (microcephaly)
Wide-set eyes (hypertelorism)
Small jaw (micrognathia)
Partial webbing or fusing of fingers or toes
High pitched cat-like cry

27. Complications Mental retardation Inability to care for self
Inability to function in society

28. Karyotype

29. Phenotype

30. Sex Chromosome Disorders
There are several disorders related to the sex chromosomes
Analyze these by asking yourself if they add or remove male or female characteristics
Example: a single X means they’ve lost some female traits, while an extra X means they gain some female traits * * *
Please take notes on everything with an asterisk!

31. Trisomy 23 Klinefelter’s Syndrome*
Trisomy 23 Klinefelter’s Syndrome
XXY

32. * Statistics Occurs in 1 in 500 to 1 in 1,000 male births
Technically, the disorder only affects males since they have a Y chromosome, but people with this disorder have both incomplete male and incomplete female characteristics because of the extra X chromosome *

33. Phenotype Physical Characteristics
Tall (around six feet)
Sparse facial and body hair
Incomplete masculinization plus feminine body (pear shaped) and body hair distribution
Enlarged breast tissue (Gynecomastia)
Small testes
Sterile
High pitched voice
NOT true hermaphrodites * * *

34. * * * Complications Infertility Low self esteem Low energy
Osteoporosis
Communication difficulties
Parents must decide whether to raise their child as male or female
Sometimes when the person grows up, they change their minds and use surgery and hormones to change their bodies * *

35. Karyotype

36. Phenotype

37. Trisomy 23 “Supermale” Syndrome*
Trisomy 23 “Supermale” Syndrome
XYY

38. * Statistics The disorder only affects males
Occurs in less than 1% of males
4% of inmates in maximum security prisons have an XYY karyotype (this is a bigger percentage than in the general population)

39. Phenotype Physical Characteristics
Tall (around six feet)
Acne
“Mentally dull”
Some studies suggest (but don’t prove) that the extra Y chromosome leads to increased aggression and violence *

40. *
Monosomy 23
Turner’s Syndrome
“XO”

41. * Statistics Affects 1 out of 3,000 live births
Only affects females, since there is no Y chromosome

42. Phenotype Physical Characteristics
Short Stature
Low hairline
Webbed neck
Drooped eyelids
Infertile
Lack secondary sex characteristics that would make them look like adult women
Will never menstruate or ovulate
Remain like immature girls throughout life * * * *

43. Complications High blood pressure Obesity Cataracts Arthritis Diabetes
Kidney abnormalities

44. Karyotype

45. Phenotype (cont.)

46. Practice Karyotypes Name the gender of each karyotype
Tell whether it is normal or not
If it is not normal, name the disorder

47. Answer: Female with Down’s Syndrome

48. Answer: Normal male

49. Answer: Klinefelter’s Syndrome (male/female)

50. Answer: Normal Female

51. Answer: “Supermale”

52. Answer: Male with Down’s Syndrome

53. Answer: Turner’s Syndrome (Immature Female)

54. How to Remember Klinefelter’s vs. Turner’s vs. Supermale*
How to Remember Klinefelter’s vs. Turner’s vs. Supermale
Klinefelter’s is a long word, it has an extra chromosome (XXY)
Turner’s is a shorter word, it has a missing chromosome (X alone)
Supermale (XYY) has a double Y, Klinefelter’s (XXY) has a double X

55. Go to Worksheet!!!!!!!
1. Complete Crossword puzzle – fantastic review for Vocab Exam next week! 2. Complete Punnetts on back – marvelous practice for Punnett Exam next week!