Chromosome Abnormalities

Question 1

What are the numerical chromosome abnormalities

Answer 1

Trisomy

Monosomy

Polyploidy

Question 2

Define trisomy

Answer 2

47,XX,+21

Question 3

Define monosomy

Answer 3

45,X

Question 4

Define polyploidy

Answer 4

69,XXY

Question 5

What are the structural chromosome abnormalities

Answer 5

Translocation

Inversion

Duplication

Deletions

Question 6

Define translocation

Answer 6

t(1;2)(q24;p12)

Question 7

Define inversion

Answer 7

inv(7)(q11q21)

Question 8

Define duplication

Answer 8

dup(11)(p14p15)

Question 9

Define deletions

Answer 9

del(22)(q11q12)

Question 10

What can cause numerical chromosomal abnormalities

Answer 10

Nondisjunction

Question 11

What can cause structural chromosomal abnormalities

Answer 11

Reciprocal translocation (e.g. becomes unbalanced)

Question 12

Describe F.I.S.H

Answer 12

Fluorescence in situ hybridisation

DNA probes labelled with fluorophores

Hybridised directly to the chromosome preparation or interphase nuclei

Can look for microscopic deletions using locus specific probes

Can ‘count’ the chromosomes in interphase nuclei

Provides quick results without the need to look at chromosomes or provides more detailed information

Question 13

Describe microarrays

Answer 13

Improves resolution for detection of cytogenetic abnormalities

Able to assess colour ratios

Investigate genome at a higher resolution than possible by microscopy

Question 14

Define constitutional abnormalities

Answer 14

Occur at gametogenesis

Affects all cells of the body

Heritable

Question 15

Define acquired abnormalities

Answer 15

Changes occur during lifetime

Restricted to malignant tissue

Not heritable

Question 16

Define benign polymorphism

Answer 16

A change in the genetic sequence that is not thought to cause disease