Genetics Testing Techniques and Application Flashcards
Genetic Testing Methods
what might be some different scopes of analysis?
- differs according to scope of analysis
- specific location in 1 gene
- more than 1 diff location in same gene
- entire gene sequence
- most of sequence of protein-coding are of the genome (exome)
- most of sequence of whole genome
scope of analysis defines the test to do
Inherited testing
- if we know exact familial variant
- one or more variant associated with disease in question
- one or more variant common among certain population
- more than 1 testing method can be bundled together and needed to get better sensitivity
- insurance billing and reimbursement
Tumor testing
- depnds on goal
- diagnostic testing
- prognosis testing
- treatment
Single gene sequencing
what is it?
1 main type - what is newer?
- determines order of nucleotides
- compares pt sequence to reference sequence
- Sanger sequencing
- multiple next gen sequencing (faster, bigger scope)
detects single nucleotide changes
Single gene sequencing
When to use it? (2)
When not to use it? (3)
- when family mutation is not known
- one specific gene is accompanied by condition we are monitoring or detecting
- when family mutation is known (use targeted mutation)
- family history suggestive of more than 1 hereditary syndrome
- syndrome has multiple candidate genes (use a panel)
Deletion/Duplication analysis
AKA CNV analysis
consist of molecular probes with fluorescent tags that attach to a specific DNA sequence
- detect small deletions or duplications (FAR)
Deletion/Duplication analysis
When to use it? (2)
When not to use it? (2)
- use when deletions/dup are accompanied with condition in question (spinal muscular atrophy)
- gene sequencing is negative but there is a high possibility of genetic involvement in condition tested
- when single gene sequencing didn’t give any results that showed mutations
- don’t use if family mutation is known and is not related to CNV
- more than 1 hereditary syndrome involved (use panel)
Targeted Mutation Analysis
AKA Mutation probe, panel
- molecular probes attach to a specific string of nucleotides that are associated with a certain disease
- fluorescent probe attaches to abnormal nucleotides - looking for diff markers and finding the mutation known
Targeted Mutation Analysis
When to use it? (2)
When not to use it? (3)
- use when family mutation is known
- when we are looking for one or few specific variants (3 site testing for breast or ovarian cancer)
- don’t use when family mutation is unknown (use gene sequencing or multi panel)
- more than 1 hereditary syndrome (panel)
- multiple candidate genes equally possible
Multi-gene panels
AKA Next-generation sequencing (NGS)
compares patient sequence to a reference sequence
Multi-gene panels
When to use it? (3)
When not to use it? (2)
- use when family mutation is unknown
- multiple candidate genes
- more than one hereditary syndrome
- don’t use if family mutation is known (use targeted mutation)
- one gene is likely to be associated with disease of investigation
Whole genome/exome sequencing
Whole exome: analysis of protein coding portion of gene
Whole genome: analysis of coding, regulatory and unknown function regions
Whole genome/exome sequencing
When to use it? (2)
When not to use it? (2)
- use when other testing have no success and hereditary factors strongly suspected
- when more than 1 family member avail for testing (1st or 2nd degree relative)
- don’t use when it is better to use other targeted genetic testing
- when relatives are not available to participate
What are genetic disorders?
what is it caused by? (4)
- disease caused in whole or in part by a change in DNA sequence away from normal sequence
caused by mutation in:
- one gene (monogenic)
- multiple genes (multifactorial inheritance)
- combo of gene mutations and environmental factors
- damage to chromosomes (number or structure of entire chromosomes which carry genes)
group of inherited diseases of blood that affect person’s ability to produce hemoglobin resulting in anemia
Thalassemia
causes the body to produce thick, sticky mucus clogging lungs, leads to infection, blocks pancreas, stops digestive enzymes from reaching intestine where they are required in order to digest food
Cystic fibrosis (CF)
which drugs are D2 receptor antagonists?
where is their site of action?
phenothiazines - CTZ
metoclopramide - CTZ and GI
domperidone - CTZ
droperidol, haloperidol - GI
site of action for 5-HT3 drugs?
CTZ
GI - fundus, corpus, antrum
vagal sensory afferent neurons - slow transit leads to constipation
