Multifactorial/Common Complex Disorders Flashcards Preview

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Flashcards in Multifactorial/Common Complex Disorders Deck (12):

What are the causes of common complex conditions

Multifactorial inheritance
Mendelian inheritance


What are the causes of multifactorial inheritance

Inherited predisposition due to multiple genetic factors


How do we identify genetic and env. influences

Observational studies of incidence of disease in different groups
Eg. twin studies, adoption studies


What is the heritability of condition

Proportion of aetiology ascribed to genetic factors


What does polygenic inheritance mean

Each gene makes small additive effect to final phenotype
Basis for continuous traits following normal distribution


What is the threshold libability

Above this liability, people will develop multifactorial disease


What are the factors that increase probability of recurrence

High heritability
Person with condition of more rarely affected sex
Severe/early onset
Multiple family members affected


How do we identify genetic factors involved in condition

Identify pedigree pattern
Diagnose disorder
Identify genes using linkage or gene tracking
Do genes in the location affected have functions suggesting cause of disease
Genes in location then sequenced for pathogenic mutation


What is association

Occurence together in population more often than can be readily explained by chance of >2 traits


What are the questions to ask once area of chromosome is identified

Is it protein coding region
Are there controlling elements in area
Any variants


Why is genomics important in clinical practice

Targeted treatment
Genetics can alter drug response
Can change environment for genetically susceptible individuals


What does mutation in SNP suggest according to GWAS

May not be direct cause of disease but serves as marker of other genetic factors in chromosomal region