Cytogenetics 1

Question 1

short arm and goes up

Answer 1

p

Question 2

long arm and goes down

Answer 2

q

Question 3

centromere in the middle

Answer 3

metacentric

Question 4

centromere in the upper part

Answer 4

submetacentric

Question 5

centromere at the tip

Answer 5

acrocentric

Question 6

exchange of material between two or more chromosomes

Answer 6

translocation

Question 7

loss of material

Answer 7

deletion

Question 8

gain of material

Answer 8

duplication

Question 9

alteration within a chromosome

Answer 9

inversion

Question 10

numbers stay at 46

Answer 10

structural

Question 11

gain or loss of a chromosome–> number changes from 46

Answer 11

Numerical

Question 12

trisomies that are compatible with life

Answer 12

13, 18, 21 and X/Y

Question 13

Is a loss of sex chromosome compatible with life

Answer 13

yes

Question 14

47, XX/XY, +21

Answer 14

Down

Question 15

47, XX/XY, +18

Answer 15

Edwards

Question 16

47, XX/XY, +13

Answer 16

Patau

Question 17

small size, small head circumference - congenital heart defects - overlapping finger - rocker bottom feet - very poor prognosis, only 5% survive beyond 1 year

Answer 17

Edwards syndrome features

Question 18

single palmar crease - sandal gap - small ear - nuchal skin fold - clinodactyly - hypotonia - hyperflexibility of joints

Answer 18

Downs’ syndrome: newborn features

Question 19

intellectual disability - congenital heart disease gastrointestinal abnormalities -atlantoaxial instability -strabismus - thyroid abnormalities -leukemia

Answer 19

Downs syndrome: associated findings

Question 20

scalp defects, microcephaly, micropthalmia, holoprosencephaly, clef lip and palate - CHD - polydactyly - renal anomalies - very poor prognosis

Answer 20

trisomy 13 features

Question 21

sex chromosome changes (4)

Answer 21

(1) turner syndrome (2) klinefelter syndrome (3) 47, XYY (4) 47, XXX

Question 22

only one X chromosome present no other X or Y

Answer 22

turner syndrome

Question 23

1 in 2,00-2,500 female births - lymphedema in infancy - bicuspid aortic valve, coarctation of aorta - low posterior hairline, webbed neck, widely-spaced hypoplastic nipples-horshoe kidney -cubitous valvus of elbow

Answer 23

turner’s syndrome

Question 24

45, X

Answer 24

turners ~50%

Question 25

46, X abnormal X

Answer 25

turners syndrome

Question 26

1 in 500 - 1,000 male births - tall stature, long limbs -learning differences - gynecomastia - small testicles - infertility due to hypogonadism with oligospermia/ azoospermia

Answer 26

klinefelter syndrome

Question 27

two x chromosome and one small Y

Answer 27

klinefelter

Question 28

- 1 in 1,000 female births -speech delay, IQ 10-15 points below siblings -increased risk for infertility - most offspring are chromosomally normal

Answer 28

47, XXX

Question 29

- 1 in 1,000 male births - IQ 10-15 points below siblings - may be at increased risk for behavioral problems- impulsivity and emotional immaturity - most offspring are chromosomally normal - risk of infertility issues

Answer 29

47, XYY

Question 30

compensates for dosage difference between males and females

Answer 30

x- inactivation

Question 31

is x inactivation reversible?

Answer 31

Yes!

Question 32

steps involved in X-inactivation (3)

Answer 32

(1) Counting (2) Choice (3) cis inactivation

Question 33

Counting

Answer 33

mechanism to assess how many X-chromosomes present

Question 34

Choice

Answer 34

random if both chromosomes normal

Question 35

Abnormal X

Answer 35

inactivated if has XIST

Question 36

translocation between X and autosome

Answer 36

normal X inactivated

Question 37

Unbalanced X translocation

Answer 37

Abnormal X inactivated

Question 38

counting requires at least one x chromosome is

Answer 38

active

Question 39

Cis inactivation spreads in

Answer 39

both directions

Question 40

amount of genes that escape inactivation

Answer 40

15%

Question 41

XIST locus in

Answer 41

Xq13

Question 42

cis inactivation in different tissues

Answer 42

variable expression

Question 43

single chromosome changes are most often

Answer 43

non-disjunction

Question 44

Diploid

Answer 44

2 copies for every chromosome

Question 45

haploid

Answer 45

1 copy of every chromosome

Question 46

triploid

Answer 46

3 copies of every chromosome

Question 47

cause of triploid (3)

Answer 47

(1) 2 sperms fertilizing 1 egg (2) sometimes found in prenatal analysis (3) frequently seen in missed abortion material

Question 48

69, XXY

Answer 48

three copies of every chromosome

Question 49

nondisjunction during meiosis gives rise to

Answer 49

trisomy in the conceptus

Question 50

meiosis and nondisjunction can occur

Answer 50

with any chromosome not just 13, 18, 21 but conceptus may not be viable

Question 51

what can occur during fetal development?

Answer 51

trisomic rescue

Question 52

trisomic rescue

Answer 52

one of the extra chromosomes is lost

Question 53

trisomic rescue can result in

Answer 53

uniparental disomy

Question 54

Answer 54

heterodisomy; three different copies of a chromosome

Question 55

Answer 55

isodosomy; two copies are the same but one is a new different copy

Question 56

Answer 56

M1 Block

Question 57

Answer 57

M2 Block

Question 58

Answer 58

normal

Question 59

Answer 59

1. isodosomy 2. heterodosomy 3. ok 4. ok 5. uniparental disomy 6. ok 7. ok

Question 60

which X gets inactivated if a fetus has a blananced X- autosome translocation

Answer 60

Normal X is inactivated

Question 61

infant that presents with oral and/or facial clefts, microphtalamia, cutis aplasia and cardiac abnormalities

Answer 61

Patau