Chap 8- Identifying disease genes Flashcards
1
Q
monogenic
A
influenced by one mutation
2
Q
oligogenic
A
decided by mutations in a few genes
3
Q
polygenic
A
very complex disorders decided by mutations in multiple genes and other factors
4
Q
genetic risk factor
A
- put you at risk for developing certain diseases
- aka susceptibility factors
5
Q
protective factors
A
factors that can protect us from developing certain diseases/ lower diseases susceptibility
6
Q
what are the general types of genetic testing done?
A
- screenings- usually in pregnant mothers, newborns, or carriers
- diagnostic tests
- prediction tests- usually in asymptomatic people who have familial risk
7
Q
How do you evaluate a genetic test?
A
- ACCE
- Analytical validity
- Clinical validity
- Clinical utility
- Ethical validity
8
Q
sensitivity
A
- proportion of all people who have the disease who are correctly identified as such
- picking up true positive
9
Q
specificity
A
- proportion of all people who do not have the condition and who are correctly identified as such
- picking up true negative
10
Q
ethical considerations with genetic testing
A
- consent for genetic testing
- sharing of genetic info
- confidentiality of test results
11
Q
right to an open future principle
A
- disclosure of any genetic info from test could infringe on a child’s future autonomy
12
Q
what is 3 person IVF treatment
A
- baby born from mother who has mitochondrial disorder, father, and a mother egg donor
- take anucleated egg from mother with mitochondrial disorder and fertilize it with sperm
- take nucleus from donor egg and use it in fertilized egg
- approved only in UK
13
Q
pyrosequencing
A
- sequential enzyme reaction that detects pyrophosphate when nucleotide is added to DNA
- can be used to determine mutant and normal sequences
- helpful in heterogeneous tumor samples
14
Q
chromosome FISH
A
- FISH= fluorescence in situ hybridization
- higher resolution than karyotyping
- fix chromosomes, treat them to denature DNA, insert fluorescently labeled probes
- location of probes recorded
- cells rested in metaphase
- helps to identify more specific mutations compared to karyotyping
15
Q
principle of genetic linkage
A
- alleles very closely located will travel together
- chance of being separated during recombination is very low
16
Q
what is the LOD score?
A
- chance that genes will be inherited together
- if score is 3 or higher, genes are close together and will likely be inherited together
17
Q
restriction fragment length polymorphism (RFLP)
A
- used to map genes to defined subchromosomal regions
- similar to mini and micro satellites
- restriction enzymes cut DNA at specific sites
- run fragments on the gel to identify someone (everyones cuts will look different)
18
Q
exome sequencing
A
- widely used to identify rare diseases
- exome- all exons in genome
- introns are disposed of and sequence only the exons
- very cost effective and fast
19
Q
phenocopy
A
- diseases that closely mimic phenotype but do not have genotype commonly associated with disease
20
Q
Genome-Wide Association Studies (GWAS)
A
- studies conducted in huge populations
- look for SNPs associated with certain complex diseases
- allows for better strategies to detect, treat, and prevent disease
21
Q
GWAS and Inflammatory Bowel Disease
A
- succesful in identifying genes for Crohn’s and ulcerative colitis
- in both cases disease resulted from abnormal immune response to intestinal microbiota
- autophagy process dysregulation
22
Q
heat maps
A
- show how strongly diseases are associated with each other
- compare genetic profiles of different diseases
- strong associations are indicated by 95 or higher
23
Q
FUT2 allele
A
- codes for fucosyltransferase enzyme
- mutation makes person immune to norovirus
- makes them mores susceptible to Crohn’s and type 1 diabetes
- FUT2 is required for norovirus to invade cells, but mutation causes change in microbial flora -> Crohn’s
24
Q
epistasis
A
- interaction between 2 or more genes to control a single phenotype
- genes that belong to same biological pathway are likely to interact
25
endophenotype
- behavioral component of diseases
- i.e. have a gene type that makes a person overeat
- due to overeating they are at a higher risk for diseases associated with obesity
26
case control studies
- most widely used for studying genetic and environmental factors of complex diseases
- usually retrospective
- depend on recall which introduces hugh personal bias
27
cohort studies
- prospective
- best to identify role of environment in disease process
- study individuals over long time before onset of disease
28
what is the thrifty phenotype
- adaptation of fetus that maximizes chance of surviving in environment with limited nutrition
- in adult life the person has altered metabolism
- when food is readily available they are more likely to develop type 2 diabetes, obesity, and HTN
