| Question |
Answer |
| Epidemiology |
The study of agents affecting health and illness in populations and the foundation of public health and preventative medicine |
| Attributable fraction |
That proportion of a disease that could be eliminated by removing the risk factor (allelic variant or environmental exposure for example) from the population. |
| Odds Ratio |
The odds of a disease occurring in one group compared to the odds of it occurring in a comparison group. Most often applied in case-control studies. |
| Relative Risk |
Probability of a disease occurring in an exposed compared to an unexposed group. Most often used in controlled trials and cohort studies. |
| Genome Wide Association Study |
A comprehensive study of a set of SNPs across the entire genome to determine association with a disease and with no prior hypothesis on which SNP/gene might be associated |
| Twin design |
compares the similarity of identical twins who share 100% of their genes, to that of dizygotic or fraternal twins, who share only 50% of their genes. |
| Twin studies help researchers understand |
the role of genetic effects, and the effects of shared and unique environment effects. |
| segregation analysis |
The determination of the number of progeny that have inherited distinct and mutually exclusive phenotypes. compare all possible models to observed data |
| H squared |
The proportion of the total variance for a trait caused by genes H is approx=1 with height |
| odds ratio |
the ratio of the odds of an event occurring in one group compared to the odds of it occurring in another group |
| The odds ratio is used for |
case-control studies and retrospective studies AND for the approximation the relative risk for small probabilities |
| Relative risk |
probability of Dz occurring in exposed group compared to unexposed. 2) Used in randomized controlled trials and cohort studies |
| Genome Wide association |
For identification of common variants in common/complex traits 2) involves rapidly scanning markers across the complete sets of DNA, or genomes, of many people to find genetic variations associated with a particular disease. |
| what is the problem with genome wide association |
problem is multiple comparison AND Billions of data points |
| How can Genome wide association be useful |
researchers can use the information to develop better strategies to detect, treat and prevent the disease. also pharmacogenetics and personalized medicine ex) asthma, cancer, diabetes |
| model for the implementation of related genetic testing in the market |
variability in dosing of warfarin attributed to genetic variants. The incorporation of genetic testing for these variants (i.e. those at risk) is the model |
| SNPS and Prostate Cancer for example_Odds ratios based on |
number of SNP risk factors and family history positive |
| Microbiome |
is that collection of microbes in/on you |
| Metagenome |
is the genomic content of you |
| Cohort study |
often undertaken to obtain evidence to try to refute the existence of a suspected association between cause and disease |
| A cohort is |
a group of people who share a common characteristic or experience within a defined period |
| The 2X2 table |
used to determine significance of risk and its magnitude (chi squared) by recording and analysing the relationship between two or more variables |
| Relative risk and Odds ratios are the same when |
the disease is rare in a population |
| clinical validity of a test |
important to consider in cohorts to determine if a test should become a clinical tool; describes both the positive and negative value for a test |
| Positive predictive value |
Fraction of people with risk variant who will develop disease |
| Negative predictive value |
Fraction of people without risk variant who will not develop disease |
| PPV is high for |
rare Mendelian disorders like cystic fibrosis |
| PPV is low for |
complex traits like diabetes |
| An allelic variant with a small RR/OR ratio |
may have substantial public health impact if allele is common. attributable fraction measures the impact (smoking cessation programs driven by estimates of their effect on disease prevalence) |
| Identifies many alleles associated with small (OR 1.1-1.5) risks for common complex traits |
Genome Wide association studies |
| environmental variables may be well defined for some.... |
disorders and have similar numerical risk profiles (OR) |
| By combining multiple alleles each with additive risk |
individual risk profiles can be developed so that a small number of persons can be identified as "at risk" |
| Direct to consumer testing and genetics |
commercial entities made tests available for common alleles associated with predisposition to common traits that include a genetic risk 2) use DNA chips 3) test for SNP variants |
HHS Shrek
