Hereditary Haemachromatosis involves excessive iron absorption
Why is HH dangerous?
Iron builds up in tissues
Iron damages blood vessels
Iron is poisonous
How is HH inherited?
Autosomal dominant
X linked recessive
Autosomal recessive
HH is an example of a founder mutation
pC282Y and pH36D can cause HH in what forms?
As heterozygotes
As homozygotes
As compound heterozygotes
What is the test for HH?
Ferratin levels in the blood
Iron absorption by gut
Free blood iron level
Which exon contains the p.C282Y mutation?
3
4
5
How can we amplify the area around the suspected mutation?
PCR
Using specific primers
Fluorescent based DNA sequencing is used to ascertain the exact sequence
Dideoxysequencing relies on what?
Chain terminating nucleotides
Chain bending nucleotides
Chain mutating nucleotides
Fluorophores of different wavelengths are used to differentiate the four chain terminating bases
After the amplification, how do we separate the product?
By size on a gel
By size on a not gel
A laser scanner reads the different flurophores as the produces come in, from which it can form a sequence
How are chromosomal level variations tested?
Karyotyping
Using SNP's
The 'Standard FISH' is the 'hybridisation of multiple chromosome specific probes
FISHing can be used to detect DiGeorge syndrome
What do the probes in FISHing usually look for
Smallest area of overlap between possible deletions
Largest area of overlap between possible deletions
The ends of telomeres
Why is the end of the telomere looked for in Dual Probe FISHing?
To ensure there's a correct no of each chromosome
So if there's no binding to smallest area of overlap, it's not because the chromosome itself is missing
To ensure the chromosome is the correct shape
FISHing can be used for testing chromosome rearrangement
In a BCR-ABL related cancer, (assuming you were using a Red probe for the BCR gene and a green probe for the Abl gene) what would you see if you performed a FISH test?
Two red, two green
One red, one green, two yellow
Four red
In the case of novel clinical pathologies, you scan the entire genome for CNV's
How does Array Comparitive Genomic Hybridisation work?
Create an array (slide/multiple tubes of liquid samples) of probes
Probes designed to overlap all along the genome (as many base pairs apart as necessary depending on specificity)
These probes should hybrdise to tested DNA
The level of hybridisation of each probe can be used to determine deviations from norm
Assuming the highest band shows the wild type signal, what type of mutation has occurred here?
Deletion
Insertion
Duplication
Testing for CNV's will occur before testing for mutations
When exon sequencing, first amplify your exons
What is the problem with Next generation sequencing?
It generates masses of information
It generates sequences at random
It's difficult to tell which mutations are pathogenic
Assuming a person has a wide number of mutations (most people do) what do you discount?
SNP's common in the population
Synonymous variants
Heterozygous variants
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