Chromosomes to Bases Flashcards
how many chromosomes does a normal human have?
46
what does 46 XX mean?
female
what does 46 XY mean?
male
how can chromosomes be recognised?
banding patterns
length
position of the centromere
describe the overall structure of a chromosome
telomeres at either end
short arm (p) and long arm (q)
centromere between the arms
what is an acrocentric chromosome?
one where the short arm is so small it is negligible
what are the two types of chromosome rearrangements?
balance
unbalanced
what is a balanced chromosome rearrangement?
all chromosomal material is present
what is an unbalanced chromosome rearrangement?
extra or missing chromosomal material
what is aneuploidy?
a whole extra or missing chromosome
what is translocation?
rearrangement or chromosomes
what are insertions and deletions?
missing or duplicated material
what is 47 XY + 21?
Down syndrome
what is a robertsonian translocation?
when two acrocentric chromosomes are stuck end to end
what chromosomes can be affected by robertsonian translocation?
14
21
what does trisomy 14 cause?
miscarriage
what does trisomy 21 cause?
Down syndrome
what does trisomy 18 cause?
Edwards syndrome
what is 47 XY+18?
edwards syndrome
what is 45 X?
Turner syndrome
why is X chromosome aneuploidy better tolerated than others?
due to X inactivation
what is 47 XXX?
triple X
what is 47 XXY?
klinefelter syndrome
what is a reciprocal translocation?
when parts of two chromosomes are swapped
what is the first line chromosomal genetic test?
array CGH
what type of rearrangements can be detected by aCGH?
unbalanced
how could chromosome changes result in malignancy?
activation of an oncogene
deletion of a tumour suppressor
what is the management of a malignancy with HER2 amplification?
trastuzamab
what is the treatment in a malignancy with a Philadelphia chromosome?
imatinib
