Trisomy Disorders

Question 1

Down syndrome is a disorder of what chromosome

Answer 1

Trisomy 21.

Question 2

Signs of down syndrome are?

Answer 2

Flat faces, prominent epicanthal folds, single palmer crease, duodenal atresia, Atrial septal defect.

Question 3

Later signs of Down syndrome?

Answer 3

Early onset Alzheimers and increased risk of ALL and AML.

Question 4

At what stage of meiosis is most Down syndrome associated with?

Answer 4

meiotic nondysjuntion typically in Meiosis I sometimes in Meiosis II.

Question 5

What proceedures are in place to detect Down syndrome?

Answer 5

First trimest - USS showing increased nucal translucency and hypoplastic nasal bone. Serum PAPP-A is low and Beta-hCG is increased.

Second trimester quad screen shows increased alpha-fetoprotein, increased h-CG, low estriol and increased inhibin A.

Question 6

What is Edwards syndrome?

Answer 6

Trisome 18

Question 7

What are some findings of an Edwards patient?

Answer 7

Severe intellectual disability,
rocker bottom feet, 
Micrognathia(small jaw) 
Low set ears, clenched hands with overlapping fingers, prominent occiput and cogenital heart disease. 
Usually death in 1 year.

Question 8

Test findings in Edwards syndrome?

Answer 8

PAPP-A and free beta-hCG are low in 1st trimester.

Quad screen shows low alpha fetoprotein, low hCG, low estriol and low/Normal inhibin A.

Question 9

What is patau syndrome?

Answer 9

Trisome 13.

Question 10

Signs of Patau syndrome?

Answer 10

Severe intellectual disability
Rocker bottom feet, 
Microphthalmia
Microcephaly
Cleft lip/palate
Polydactyly
Congenital heart disease
death in 1 year.

Question 11

Tests for Patau syndrome?

Answer 11

1st trimester screen - low beta-hCG, low PAPP-A and increase nuchal translucency.

Question 12

Cri du chat sundrome is where there is a microdeletion of what?

Answer 12

a deletion in the Chromosome 5 short arm (46 XX/XY del (5p-))

Question 13

What are some signs of Cri du chat?

Answer 13

Microcephaly, moderate to severe intellectual disability, high pitch crying/mewing, epicanthal folds and cardiac abnormalities - VSD

Question 14

Williams syndrome is a deletion of what on chromosome 7?

Answer 14

Long arm of Chr 7 in the region of elastin gene.

Question 15

What do the following signs indicate?

Elfin facies, intellectual diability, hypercalcamia, verbal skills, friendliness and cardiovascular problems.

Answer 15

Williams syndrome.