Week 1: Cyto, Aneuploidy, Deletions

Question 1

5 main features of T21

Answer 1

Hypotonia, ID, flat facial profile, CHD, GI anomalies

Question 2

Most common genetic cause of T21

Answer 2

Nondisjunction

Question 3

Mosacism is always a _____ event

Answer 3

Mitotic

Question 4

RR for nondisjunction T21

Answer 4

1% OR maternal age risk

Question 5

5 major features of T18

Answer 5

Hypertonia, clenched fist with overlapping 3rd and 4th finger, rocker-bottom feet, ID, hernia

Question 6

RR for T18

Answer 6

Less than 1% (since most SAB)

Question 7

5 major features of T13

Answer 7

(Midline) HPE, CL+P, polydactyly, omphalocele, ID+ seizures

Question 8

RR for T13

Answer 8

Less than 1% (since most SAB)

Question 9

5 major features of 22q11

Answer 9

Velopharngyeal incompetence, CHD, asymmetric crying facies, immunodeficiency, hypocalcemia

Question 10

Is 22q usually de novo or inherited

Answer 10

de novo

Question 11

5 major features of XXY

Answer 11

Hypogonadism, infertility, lower IQ than sibs, behaviour problems, gynecomastia

Question 12

Treatment for XXY

Answer 12

Testosterone supplementation

Question 13

5 major features of XO

Answer 13

Short stature, gonadal dysgenesis, webbed neck, CHD, transiet congenital lymphedema

Question 14

Treatment for XO

Answer 14

Estrogen replacement therapy

Question 15

Risk for 45, X/ 46, XY Mosaics

Answer 15

Gonadoblastoma

Question 16

What is used to stop the cell cycle in metaphase when making a karyotype

Answer 16

Colchicine

Question 17

Best uses for FISH

Answer 17

Partial/full aneuploidy–but you must known what you are looking for

Question 18

Array CGH cannot detect

Answer 18

Balanced translocations, triploidy

Question 19

SNP-array is useful for detecting:

Answer 19

Consanguinity (ROHs), triploidy, UPD

Question 20

4 posible gametes for reciprocal translocation carrier

Answer 20

Normal, Balanced, Unbalanced (two forms)

Question 21

3 major features of Cri du Chat

Answer 21

Cat-like cry, microcephaly, low birth weight

Question 22

Where is deletion in Cri du Chat

Answer 22

5p

Question 23

3 major features of Wolf Hirschhorn

Answer 23

Greek warrior helmet appearance, FTT, ID

Question 24

Where is deletion in Wolf Hirschhorn

Answer 24

4p16.3

Question 25

3 major features of 1p36.3 del

Answer 25

severe ID, seizures, behaviour problems

Question 26

Where is deletion in 1p36.3

Answer 26

1p36.3

Question 27

3 major features of William's Syndrome

Answer 27

Elfin face, outgoing personality, supravalvular aortic stenosis

Question 28

Where is deletion in William's Syndrome

Answer 28

7q11.23

Question 29

T/F: X-inactivation affects all genes

Answer 29

False

Question 30

2 major features of Miller Dieker Syndrome

Answer 30

Type 1 lishencephaly, dysmorphic facies

Question 31

Where is deletion in Smith Magenis

Answer 31

17p11.2

Question 32

3 major features in Smith Magenis

Answer 32

Self-destructive behaviour, peripheral neuropathy, ID

Question 33

Deletion in Prader Willi

Answer 33

15q11-q13

Question 34

What parent's copy is missing in PWS

Answer 34

Dad

Question 35

What parent's copy is missing in Angelman

Answer 35

Mom

Question 36

Where is deletion in Angelman

Answer 36

15q11-q13

Question 37

3 major features of Prader Willie

Answer 37

Infantile hypotonia, hyperphagia, hypogenitalism

Question 38

3 major features of Angelman

Answer 38

Seizures, Unusual laughter, ataxic gait

Question 39

Where is duplication in BWS

Answer 39

11p15

Question 40

3 major features in BWS

Answer 40

Macrosomia, Macroglossia, Omphalocele

Question 41

Alternate segregation usually leads to balanced or unbalanced gametes?

Answer 41

Balanced

Question 42

Adjacent segregation usually leads to balanced or unbalanced gametes?

Answer 42

Unbalanced

Question 43

Centromeres in Adjacent 1

Answer 43

Unlike centromeres travel together

Question 44

Centromeres in Adjacent 2

Answer 44

Like centromeres travel together

Question 45

Tertiary 3:1 Segregation

Answer 45

2 normal chromosomes; 1 translocation chromosome

Question 46

Interchange 3:1 Segregation

Answer 46

2 translocation chromosomes; 1 normal chromosome

Question 47

List afrocentric chromosomes

Answer 47

13, 14, 15, 21, 22, Y

Question 48

RR if mom passes t(13;21)

Answer 48

15%

Question 49

RR if mom passes t(14;21)

Answer 49

10%

Question 50

RR if mom passes t(21;22)

Answer 50

10%

Question 51

Paracentric Inversion

Answer 51

Breaks in either short arm or long arm, no centromeres involved

Question 52

Pericentric Inversion

Answer 52

Break in the short arm and long arm, centromeres involved

Question 53

Inversions in what chromosomes are considered normal variation?

Answer 53

1, 9, 16, Y