Lecture 16 - Chromosomal Disordrs

Question 1

Areas of a chromosome?

Answer 1

p (short) arm, q (long) arm, telosmere (end of q), centromere

Question 2

Neumerical chromosomal abnormalities and cause?

Answer 2

Aneuploidy (monosomy and trisomy) caused by non-dysjunction during meiosis

Question 3

Aneuploidy of sex chromosomes?

Answer 3

Klinefelter syndrome (XXY), Turner syndrome (XO)

Question 4

Mosaicism?

Answer 4

somatic, structural or numerical, mitotic non-disjunction post zygote formation

Question 5

Translocation definition?

Answer 5

two way exchange of material between two non-homologous chromosomes

Question 6

Carrier of Reciprocal Translocation Presentations?

Answer 6

recurent miscarraiges, chromosome examination of conception products, birth of dysmorphic baby who is unbalanced carrier, oligospermia

Question 7

Inversion?

Answer 7

two breaks on single chromosome caused reach-around and re-insertion - normal phenotype

Question 8

Deletion typess?

Answer 8

Terminal or interstitial

Question 9

When to do conventional (G-banding) karyotpe analysis?

Answer 9

suspected congenital disorders e.g. down’s syndrome, cancer/leukemia

Question 10

FISH?

Answer 10

Fluorescence In Situ Hybridisation - using DNA to located its origin on a chromosome; benefit is can be done on any nucleated tissue