Term
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Definition
Used to determine if there is a genetic component in certain diseases
Important for multifactorial diseases
Concordance of monozygotic twins is compared with concordance of dizygotic twins |
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Term
| Incidence of multifactorial disorders |
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Definition
At birth: 3-4%
By 1st year: 6-7%
Entire population: 20-40% |
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Term
| Multifactorial disorders and malformations |
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Definition
Almost 40% of malformations in newborns are due to multifactorial disorders
ex. cleft palate |
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Term
| Examples of multifactorial disorders |
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Definition
NTD
Hydrocephalus
Cleft lip
Congenital heart defects
Diabetes
Schizophrenia |
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Term
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Definition
| Most are due to multifactorial disorders |
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Term
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Definition
| Some disorders occur more frequently among relatives of a single family when compared with the entire population |
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Term
Measuring familial aggregation using relative risk ratio
lamba r |
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Definition
| measure frequency of disease among relatives of an individual compared with frequency of disease among general population |
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Term
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Definition
Comparison of selected individuals with selected controls
ex. Study of siblings of MS patients showed they had higher risk of developing MS when compared with control group without MS siblings |
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Term
| Heritability of multifactorial traits |
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Definition
H = 2 (cmz-cdz)
Traits largely caused by genes will have H close to 1 |
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Term
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Definition
Underlying liability distribution in a population and a certain threshold must be passed before an individual is affected with that disease
Low threshold means individual will develop disease easier |
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Term
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Definition
Mutations in this gene lead to NTD
Instability of gene prevents recycling of THF and prevents conversion of homocyteine to methionine |
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Term
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Definition
Multifactorial disorder
Locus heterogeneity
Symptoms include encephalocele, seizures, polydactyly, craniofacial abnormalities, poor survival
AR inheritance |
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Term
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Definition
Multifactorial disorder
1% incidence
Recurrence risk increases when individual has affected relatives |
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Term
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Definition
PTPN1 gene has risky variation and protective variation
About 35% of caucasians have the risky variation
About 45% of caucasians have the protective variation |
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