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Flashcards in Down Syndrome Deck (60)
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0

Down syndrome frequency

1/700

1

Down syndrome also called

Trisomy 21

2

Down syndrome associated diseases

1. Duodenal atresia
2. Hirschsprung disease
3. Congenital heart disease (especially ostium primum-type ASD)
4. Increased risk for ALL
5. Increased risk for AML
6. Increased risk for Alzheimer (>35)

3

Down syndrome phenotype

1. Intellectual disability
2. Flat facies
3. Prominent epicanthal folds
4. Gap between 1st 2 toes
5. Brushfield spots
6. Single palmar crease

4

Most common viable chromosomal disorder

Down syndrome

5

Most common cause of genetic intellectual disability

Down syndrome

6

Down syndrome/causes of trisomy

1. 95% due to meiotic nomdisjunction of homologous chromosomes (increased with adv maternal age)
2. 4% due to Robertson translocation (14 + 21)
3. 1.% mosaicism (no maternal association)

7

Down syndrome maternal association frequencies

1:25 if mother is over 45
1:1500 if under 20

8

Second-trimester QUAD screen shows in Down syndrome

1. Decreased a-fetoprotein
2. Increased inhibin A
3. Decreased estriol
4. Increased β-hCG

9

First trimester findings in down syndrome

1. Increased nuchal translucency (UL)
2. Hypoplastic nasal bone (UL)
3. Decreased serum PAPPA-A
4. Increased β-hCG

10

Edwards syndrome also called

Trisomy 18

11

Edwards syndrome frequence

1/8000

12

Most common trisomy resulting in live birth

Down

13

2nd most common trisomy resulting in live birth

Edwards syndrome

14

Edwards syndrome age of death

Within first year

15

Edwards syndrome first trimester (Lab)

Decreased PAPPA-A and free β-hCG

16

Edward syndrome findings

1. SEVERE intellectual disability
2. Micrognathia (small jaw)
3. Clenched hands with overlapping finbers
4. Low set ears
5. Congenital heart disease
6. Prominent occiput
7. Rocker-bottom feet

17

Second trimester QUAD screen show of Edward's syndrome

1. Decreased α-fetoprotein
2. Decreased β-hCG
3. Decreased estriol
4. Decreased or normal inhibin A

18

Patau syndrome also called

Trisomy 13

19

Patau syndrome frequence

1/15000

20

First trimester pregnancy screen show for Platau syndrome

1. Decreased free β-hCG
2. Decreased PAPPA-A
3. Increased nuchal translucency

21

Platau syndrome findings

1. SEVERE intellectual finindings
2. Rocker bottom feet
3. Micropthalmia
4. Microcephaly
5. Cleft lip/Palate
6. Holoprosencephaly
7. Polydactyly
8. Congenital heart disease

22

Robertsonian translocation-chromosomes involved

13, 14, 15, 21, 22

23

Robertsonian translocation process

The long arms of 2 acrocentric chromosomes fuse at the centromere and the 2 short arms are lost

24

Robertsonian tranloctiom phenotype

Balanced translocation-normal
Unbalanced translocation-miscarriage, stillbirth, chromosomal imbalance (eg Down, Patau syndrome)

25

Cri-du-chat syndrome process

Congenital microdeletion of short arm of chromosome 5 (46,XX or XY, 5p-)

26

Williams syndrome process

Congenital microdeletions of long arm of chromosome 7 (deleted region includes elastin gene)

27

Cri-du-chat findings

1. Microcephaly
2. Intellectual disability (moderate to severe)
3. VSD
4. Epicanthal folds
5. High-pitched crying/mewing

29

Williams syndrome findings

1. Distinctive "elfin" faces
2. Intellectual disability
3. Hypercalcemia (increased sensitivity to vit D)
4. Well developed verbal skills
5. Extreme friendliness with strangers
6. Cardiovascular problems

30

22q11 deletion is due to

Aberrant development of 3rd and 4th BRANCHIAL POUCHES