down syndrome

Question 1

what is the correlation between maternal age and DS ?

Answer 1

the incidence of DS increases with maternal age

Question 2

what is the most common genetic etiology associated with down syndrome ?

Answer 2

genetic nondisjunction

Question 3

what are the other genetic etiologies of down syndrome ?

Answer 3

unbalanced translocation

mosaic

Question 4

what are the acrocentric chromosomes found in the body normally ?

Answer 4

13 
14
15 
21 
22 
and the Y chromosome

Question 5

what are the types of transolcation ?

Answer 5

reciprocal

robertsonian

Question 6

what are the types of robertsonian translocation ?

Answer 6

balanced and unbalanced ( according to genetic data )

Question 7

carriers of down have which genetic predisposition ?

Answer 7

balanced robertsonian , phenotypically normal

Question 8

what does the karyotype of a balanced robertsonian look like ?

Answer 8

has less than normal in terms of count

but has the complete genetic data

Question 9

how does an unbalanced robertsonian look like on karyotyping ?

Answer 9

normal count

additional genetic information

Question 10

what does somatic mosaicism show ?

Answer 10

some cells have the trisomy others don’t

phenotypically hard to tell if the patient has down

Question 11

what tests are done to diagnose DS inn the first trimester ?

Answer 11

nuchal translucency ( 11-13 weeks)
serum HCG
PAPP-A

Question 12

what are the tests done in the second trimester to diagnose DS ?

Answer 12

quad screening 
serum HCG 
unconjugated estriol ( marker of a healthy fetus)
AFP 
inhibin level ( DS marker )

Question 13

when can NIPT be done ?

Answer 13

10-11 weeks

Question 14

what are the invasive methods of diagnosing DS ?

Answer 14

amniocentesis
CVS
chromosomal testing

Question 15

what is the cause of constipation in DS ?

Answer 15

hirschsprung disease

Question 16

what are the physical findings associated with downs ?

Answer 16

brachycephaly and microcephaly 
upward slanting of palpebral fissure 
epicanthal folds 
flat nasal bridge 
protruded tongue 
small ears, folded ear helix

Question 17

what are the muscoskeletal findings in DS ?

Answer 17

simian crease in hand
sandal gap between 1st and 2nd toe
clinodactyly of the 5th finger

Question 18

where do we find bitot spots ?

Answer 18

vitamin A deficiency

Question 19

where do we find kolpik spots ?

Answer 19

measles

Question 20

where do we find brushfield spots ?

Answer 20

down syndrome

Question 21

what is the most common CHD associated with DS ?

Answer 21

VSD

Question 22

what are the GIT involvements with DS ?

Answer 22

hirschsprung disease
duodenal atresia
imperforate anus

Question 23

what should be done for the OSA occuring inn DS ?

Answer 23

overnight polysomnography before the age of 4 years

Question 24

what is the most common form of AML associated with DS ?

Answer 24

acute megakaryocytic leukemia

Question 25

what are the endocrine complications associated with DS ?

Answer 25

hypothyroidism 2ry to congenital hashimoto thyroiditis

Question 26

what are the possible skin manifestations associated with DS ?

Answer 26

cutis marmorata

Question 27

what is the chance of having a DS baby if one of the parents is normal and the other is a carrier ( balanced robertsonian translocation ) ?

Answer 27

30%