2. Each person is made in God’s image
(Gen. 1:27).

6.  50% of spontaneous abortion are chromosomal abnormal
 Mostly triploidy. 45 XO, trisomy 16
 98% of fetus with turner abort
 Generally 6/1000 the incidence of chromosomal
abnormalities

7.  Unexplained infertility
 Multiple abortion >2
 Prior case of defective baby
 Presence of congenital
anomalies
› 45% have minor single
anomalies
› 9% 3 minor anomalies
› 1.5% have major anomaly
 2 or more major anomalies
may represent genetic
syndrome or chromosomal
abnormalities(10%).

10. `

11. 1. Klinefelter syndrome- XXY
 male in spite of having 2 X chromosomes or with a 44-XXY
chromosomes.
The Sperm containing both X and Y combines with an egg containing the X, results in a male child.
The egg may contribute the extra X chromosome.

12.  Males with some development of
breast tissue normally seen in
females.
 Little body hair is present, and such
person are typically tall, have small
testes.
 Infertility results from absent
sperm.
 Evidence of mental retardation may
or may not be present.

13. 2. Turner syndrome –XO
 have only 45 chromosomes ( 2n-1)
 -externally female in spite of the presence of only one X
chromosomes which are short and flat chested like those with XXX
syndrome

15. 3. Jacob’s Syndrome- XYY (Criminal syndrome)
 XYY syndrome is an aneuploidy (abnormal number) of the sex
chromosomes in which a human male receives an extra Y-chromosome

16.  causes no unusual physical
features or medical problems.
 may be slightly taller than
average
 May have more severe acne
than normal.
 Skeletal malformations may
also accompany
 includes large hands and
feet,
 have normal sexual
development and are able to
conceive children.

17. 4. Triple-X- superfemale, metafemale, XXX
 -individual has 47 chromosomes (2n +n)
 affects about 1 in 1,000 females.
 usually results from an error in the formation of a
mother's egg cell or a father's sperm cell.
 Sometimes, it occurs as a result of an error early in
the embryo's development.

18.  physically and mentally normal
 May include hypertelorism, epicanthal folds, depressed nasal
bridge
 Delay in growth and mental development, when present, is
usually mild.
 Occasionally associated with Prader-Willi syndrome.

19. 5.YO
 -a condition which is lethal because x
chromosome is necessary for life

20.  Deletions (deficiencies)
 Duplications
 Inversions
 Translocations

21. Deletions (deficiencies)
- Loss of a (generally small) segment of
chromosome
A B C D E F G A B D E F G
C

22. Arise through spontaneous breakage some
chromosomes have fragile spots, radiation, UV,
chemicals, and viruses .
Ionizing radiation acts like little atomic "cannon balls",
blasting through strands of DNA or chromosomes.
Why do they rejoin?
Break points of chromosomes are highly reactive ("sticky"),
whereas normal ends of chromosomes are capped by
telomeres, which do not readily bond to other molecules.

23. Deletion disorder in human:
1. Cri- du -chat, or cat-cry
syndrome.
 - Individuals with this syndrome
have high pitched, plaintive cry,
very similar to that of a kitten in
distress.
represent a loss in chromosomal
material.

24. Mental retardation
Slow motor skill development
Low birth weight and slow
growth
Small head (microcephaly)
Partial webbing of fingers or
toes
Wide-set eyes
(hypertelorism)

25. Fragile Sites
 are weak points at specific locations in
chromatids
 is a place where part of a chromosome
attached to the rest of the
chromosome. They have been identified
in sex chromosomes as well as on
autosomes.
EX.
2. Fragile X syndrome (FXS), Martin–Bell
syndrome, or Escalante's syndrome (more
commonly used in South American
countries), is a genetic syndrome that is the
most common known single-gene cause of
autism and the most common inherited
cause of intellectual disability

27.  May arise
through unequal
crossing over
A B C D E F G
A B C D E F G
x
A B C D E G A B C D E F F G
Deletion Duplication
Changes in the numbers of genes

28.  Large deletions will most probably be lethal
 Smaller deletions may allow survival
 Cri-du-chat syndrome - Micro deletion of chromosome 5
 DiGeorge syndrome - Micro deletion of chromosome 22
 Schizophrenia & Obsessive Compulsive Disorder
-Micro deletion of chromosome 22 associated
 Angelman syndrome- Micro deletion of chromosome 15
 Prader-Willi syndrome- Micro deletion of chromosome 15

29. Prader-Willi  lack of muscle tone in newborn
 poor swallowing reflex
 as adult - gross obesity
 mean I.Q. ~ 50
 microdeletion of 15

30.  developmentally delayed
 jerky movements
 stiff, fixed smile
 uncontrolled laughter
 abnormal E.E.G., epilepsy
 microdeletion of 15

31.  Deletions (deficiencies)
 Duplications
 Inversions
 Translocations

32.  Redundant segment of a chromosome
A B C D E F G A B C D E F F G

34.  inherited neurological disorder that affects the peripheral nerves.
 individuals experience weakness and wasting (atrophy) of the muscles
of the lower legs beginning in adolescence; later they experience hand
weakness and sensory loss.
 caused by having an extra copy (a duplication) of the PMP22 gene.
 It is inherited in an autosomal dominant manner.
 Treatment : physical therapy; occupational therapy; braces and other
orthopedic devices; orthopedic surgery; and pain medications.

35.  Deletions (deficiencies)
 Duplications
 Inversions
 Translocations

36. A portion of the chromosome has
broken off
A B C D E F G H I J K
180O
A B C H G F E D I J K

37. turned upside down and reattached,
therefore the genetic material is
inverted.
A B
C
D
E
F G
• 180o reversal of chromosome segment

38. • Produced through breakage and
reassociation of chromosome
A B
C
D
E
F G

39. Inversions cause complicated synapsis at meiosis for heterozygotes
Those not containing the centromere
are called paracentric.

40. Chromatids involved in crossing over do not allow development of
functional gametes
Inversions containing the centromere
are called pericentric.

41.  May change phenotype through “position effects”
 move active genes to sites generally inactive;
 lose gene function
 move inactive genes to sites generally active;
 gain gene function
 May act to preserve blocks of genes (specific alleles) which
function well together
No gain or loss of information; just rearrangement of genome.

42.  Deletions (deficiencies)
 Duplications
 Inversions
 Translocations

43. Reciprocal Translocation: Exchange of segments between non-homologous
chromosomes
F
A
B
C
D
E
L M N
O
P
Q

44. A B C
A portion of one chromosome is transferred to
another chromosome.
O N M L
D E F
Q P
segment from one chromosome is exchanged with a segment
from another nonhomologous one, so two translocation
chromosomes are generated simultaneously.

45.  Lead to impaired fertility
› complications to synapsis and segregation
 May lead to changes in phenotype
› position effects
› human cancers and translocations

46. A B C
O N M L
D E F
Q P
A B C D E F
L M N O P Q

47.  Only 1/3 of the segregations will lead to
usable gametes
 Fertility is reduced by 2/3

48. Several human cancers are associated with reciprocal
translocations
Chronic myelocytic leukemia, is a slowly progressing blood
and bone marrow disease that usually occurs during or after
middle age, and rarely occurs in children.
 Normally, the bone marrow makes blood stem
cells (immature cells) that become mature blood cells over time.
 A blood stem cell may become a myeloid stem cell or
a lymphoid stem cell.
 A lymphoid stem cell becomes a white blood cell.
 A myeloid stem cell becomes one of three types of mature blood
cells: RBC, platelets and Granulocytes.

50. Reciprocal translocation between chr. 22 and chr. 9
9 9 22 22

51. Reciprocal translocation between chr. 22 and chr. 9
9 9 22 22
Chr. 9 segment
has an oncogene;
when moved, it
becomes active

52. Translocations between chr. 8 and one of three others:
› 8 & 2 or 8 & 14 or 8 & 22
Chr. 8 has an oncogene ( genes involved in cell proliferation)
Chr. 2, 14, 22 have genes coding for antibody production and their
enhancer genes
Oncogene becomes highly active under control of enhancers!

53.  Fusions
› two chromosomes join to form one
Fissions
• one chromosome splits to form two

54.  Polydyspondylie
› mental retardation and spinal malformations
› fusion of two chromosomes w/ loss of short
arms

55. Familial Down Syndrome
› fusion of chromosomes 14 and 21
14 21 14+21

56. synapsis
Three possible disjunctions

58. X
X

59. X
X
X
X

60. Myths and Truths about Down
Syndrome
MYTH: Down syndrome is hereditary and runs in families.
TRUTH:
• Down syndrome is hereditary in approximately 1% of all instances.
• In the other 99% of cases Down syndrome is completely random and the
only known factor that increases the risk is the age of the mother (over
35).
• Translocation is the only type of Down syndrome known to have
hereditary link.

61. Maternal Age:
Women are born with all the eggs they will ever have.
Therefore, when a woman is 30 years old, so are her eggs.
Errors can crop up in the eggs' genetic material as they age over time.
Therefore, older women are more at risk of giving birth to babies with
chromosome abnormalities than younger women.
Since men produce new sperm throughout their life, paternal age does
not increase risk of chromosome abnormalities.

62. MYTH: Children with Down syndrome must be placed in segregated special
education programs.
TRUTH: Children with Down syndrome have been included in regular academic
classrooms in schools across the country.
The current trend in education is for full inclusion in the social and educational
life of the community.
Inclusion is a right, not a privilege
for a select few

63. Human Genome Project
 It is possible to treat diseases by altering our very genes‚
giving us new ones if ours are non-functional, changing bad
genes for good ones.
The primary goal is to determine the sequence of chemical base pairs
which make up human DNA, and to identify and map the total genes of
the human genome from both a physical and functional standpoint.

64.  We need to understand that the “genome” of
individual is unique. Mapping the human genome
involves sequencing multiple variations of each
gene. There is a need to get ready , to face
courageously and to appreciate the truth that most
chromosome abnormalities can occur.
 This study is about embracing all, making a
commitment to do whatever it takes to provide each
one in the community- an inalienable right to belong,
not to be excluded. Assume then, that living and
learning together is a better way that benefits
everyone, not just children who are labeled as
having a difference.

65. Thank you for listening…
Enjoy Being Normal!