CHROMOSOMAL ABNORMALITIES

Question 1

are either numerical or structural.

• They are a very common cause of early spontaneous miscarriage.

• Usually, but not always, cause multiple congenital anomalies and learning difficulties.

Answer 1

Chromosomal abnormalities

Question 2

Variations in Chromosome Number

⚪– the usual number and sets of chromosomes

⚪ – the presence of three or more complete sets of chromosomes

⚪ – the presence of additional chromosomes or missing individual chromosomes

Answer 2

Euploidy

Polyploidy

Aneuploidy

Question 3

NONDISJUNCTION

______ of the chromosomes during division

● Meiotic - too many/few chromosomes in all cells

● Mitotic - group of cells/patch of tissue with altered chromosome number

Answer 3

Malsegregation

Question 4

Types of Polyploidy

⚪ – three sets of chromosomes

23 x 3 = 69

⚪ – four sets of chromosomes

23 x 4 = 92

Answer 4

Triploidy

Tetraploidy

Question 5

Types of Aneuploidy

⚪ – one less chromosome

(23 x 2) – 1 = 45

⚪ – one additional chromosome

(23 x 2) + 1 = 47

Answer 5

Monosomy

Trisomy

Question 6

Aneuploidy

⚪ When aneuploidy occurs in humans, syndromes can result. Examples include the following:

Answer 6

1. Trisomy 13 - Patau Syndrome
2. Trisomy 18 - Edwards Syndrome
3. Trisomy 21 - Down Syndrome
4. Turner Syndrome
5. Klinefelter (XXY) Syndrome
6. Jacob’s (XYY) Syndrome

Question 7

Mental and physical deficiencies, wide variety of defects in organs, large
triangular nose, early death

Answer 7

Patau

Trisomy 13

Question 8

Mental and physical deficiencies, facial
abnormalities, extreme muscle
tone, early death

Answer 8

Trisomy 18

Question 9

Mental deficiencies, abnormal
pattern of palm creases, slanted eyes, flattened face, short stature

Answer 9

Down syndrome

Trisomy 21

Question 10

Sexual immaturity (no sperm),
breast swelling (males)

Answer 10

Klinefelter

XXY

Question 11

Tall and thin (males)

Answer 11

Jacobs

XYY

Question 12

Tall and thin, menstrual
irregularity (females)

Answer 12

Triple X

XXX

Question 13

Short stature, webbed
neck, sexually undeveloped
(females)

Answer 13

TURNER

X0

Question 14

Survival rate is very high for this non-disjunction!

Answer 14

Down’s Syndrome

a.k.a-

trisomy 21

Question 15

• Incidence is only 1 in 6000-11, 000 live births.
• It is uncommon for fetuses with this condition to survive

Answer 15

Edward Syndrome

⚪ This karyotype demonstrates trisomy 18
⚪ Shorthand: (47, XX or XY, +18).

Question 16

⚪ 30% of these children die within the and only 10% survive one year.
⚪ There is severe mental retardation. ⚪ Other characteristics:

● elongated skull, a very feet.

narrow pelvis, rocker bottom

● the ears are often low set and the mouth and teeth are small.

● nearly all babies born with this condition die in early infancy.

Answer 16

Edward Syndrome

⚪ This karyotype demonstrates trisomy 18
⚪ Shorthand: (47, XX or XY, +18).

Question 17

⚪ Characteristics:

● Ave life span = 2-4 months

● Small at birth

● Clenched fists with overlapping fingers

● Rocker bottom feet with protruding heels

● Elongated skull

● Low set ears

● Congenital heart problems

● Mental retardation

Answer 17

Trisomy 18

Question 18

Only 1 in 15,000 live births. (most aborted naturally)

⚪ Survival:

Forty five percent die within the first month 90% by six months Less than 5% reach 3 years.

Answer 18

Trisomy 13: Patau Syndrome

Question 19

⚪ Characteristics:

● Ave life span = 6 months

● Cleft lip and palate

● Small eyes

● Polydactyly

● Congenital heart defects

● Severe CNS disorders

Answer 19

Patau’s Trisomy 13

⚪ Trisomy 13

Question 20

• having one fewer chromosome in each body cell

Answer 20

Monosomy

Question 21

1 in 2,500 births 45, X karyotype 23rd Chromosome Monosomy Nondisjunction hypogonadism in phenotypic females

No menstruation No breast development Narrow hips Broad shoulders and neck

Answer 21

Turner Syndrome

Question 22

Women with Turner’s syndrome can live relatively normal lives, though they are unable to bear children.

The phenotype of this female includes short stature, short broad neck, and a broad chest. Intelligence does not seem to be affected.

Answer 22

Turner’s Syndrome

Question 23

The Sex-linked Trisomies!

⚪_______

Shorthand: 47, XXY

⚪______

Shorthand: 47, XYY “Supermale”

Answer 23

Klinefelter Syndrome
Jacob Syndrome

Question 24

⚪ Nondisjunction of the X chromosome.

⚪ 47, XXY karyotype

⚪ The Sperm containing both X and Y combines with an egg containing the X, results in a male child.

⚪ The oocyte may contribute the extra X chromosome

● “extra inactivated X”

Answer 24

Kleinfelter syndrome

Question 25

⚪ 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 from Azoospermia.

⚪ Mental retardation may or may not be present.

Answer 25

Klinefelter Syndrome

Question 26

⚪ The cause of this condition is a deletion of about half of the short arm of chromosome 5.

⚪________ babies are severely mentally retarded, round face, low set ears, heart disease, and have a small cranium.

⚪ Occurrence:

● 1/1,000,000 live births.

● Karyotype:

46XX or 46 XY with chromosome #5 upper arm deletion.

Answer 26

Cri-du-chat

Question 27

1/10,000 – 1/25,000 Deletion in 15q1.11 - .13 Compulsive eating Obesity Poor sexual development in males

Answer 27

Prader Willi