Chromosomal Abnormalities

Question 1

Is someone with trisomy 21 classified as euploidic, polyploidic, or aneuploidic?

Answer 1

Aneuploidic.

Polyploidy is for complete sets of extra chromosomes.

Question 2

A nondisjunction event in miosis I would result in what % abnormal genes in a gamete?

Answer 2

100%

Miosis II is 50%

Question 3

Children with Downs Syndrome are at risk for aquiring an extra X chromosome in bone marrow. This leads to______

Answer 3

Acute Leukemia

48,XX,+X,+21c

c stands for constitutional.

Question 4

How is Edwards Syndrome characterized?

Answer 4

Trisomy 18:
Microcephaly, clenched hands, rocker bottom feet.

Mnemonic
When we vote, we elect the small brained people that steal our money (clenched hands).

Question 5

What occurs during a roberstonian translocation?

Is it balanced or unbalanced?

Answer 5

The long arms of 2 chromosomes join together at the centromere. Short arms also join and are usually lost.

Can be both

Normally chromosomes 13-15 and 21+22.
13;14 is most common at 75%

Question 6

46,XX,+21,der(14;21)(q10;q10)

Answer 6

Trisomy 21 caused by unbalanced Robertsonian Translocation between 14;21.

Question 7

Which type of inversion is exemplified by the following genotype?

46,XX,inv(9)(p24q12)

Answer 7

Pericentric because it crosses the centromere. Both the p and q arms are involved.

Question 8

Most people with pericentric inversions exhibit normal phenotype. What occurs during meiosis that causes problems for potential offspring?

Answer 8

Inversions form a loop during recombination. This often times results in unbalanced gametes.

Question 9

A parent with an inverted 8 chromosome is at risk for having a child with which symptoms?

Answer 9

Rec 8:

Developmental delay.

Congenital Heart disease.

Thin upper lip.

Hypertelorism-distance between organs eg wide eyes

Prevalent in Hispanic Populations

Question 10

Which type of inversion is exemplified by the following genotype?

46,XX, inv(11)(q21q23)

Answer 10

Paracentric

Question 11

A patient presenting with T cell dysfunction, hypocalemia, cleft lip/palate may have which type of syndrome?

Answer 11

Deletion or Duplication of 22q21.2 syndrome

AKA digeorge

Question 12

DS infants and children have 20-100x risk and 500x risk for which diseases?

Answer 12

ALL/AML

500x=AMKL (acute megakaryo-blastic leukemia)