Multifactorial Complex Disorders Flashcards
Which inheritance patterns are ‘classical’ / Mendelian?
- Dominant/recessive.
- Autosomal/X-linked.
Which inheritance patterns are non-Mendelian?
- Multifactorial inheritance patterns.
- Maternal (mitochondrial) inheritance patterns.
What is familial clustering?
Where the incidence of a disorder in a family is different from the incidence in the general population (such that it is clustered in the family).
What might be the objective of a twin study in gathering evidence for genetic factors in complex diseases?
To investigate the incidence in monozygotic compared with dizygotic twins.
What might be the objective of an adoption study in gathering evidence for genetic factors in complex diseases?
To investigate the incidence in adopted children of the disorders which their biological parents had.
What might be the objective of a population and migration study in gathering evidence for genetic factors in complex diseases?
To investigate the incidence in people from a particular ancestry group when they move to a different geographical area.
List 6 common complex diseases (with multifactorial inheritance) that are congenital.
1 - Cleft lip.
2 - Congenital dislocation of the hip.
3 - Congenital heart defects.
4 - Neural tube defects.
5 - Pyloric stenosis.
6 - Talipes.
List 7 common complex diseases (with multifactorial inheritance) that are adult onset disorders.
1 - Diabetes mellitus.
2 - Epilepsy.
3 - Glaucoma.
4 - Hypertension.
5 - Coronary artery disease.
6 - Manic depression.
7 - Schizophrenia.
Which gene is (partially) responsible for the development of neural tube defects?
The MTHFR gene.
What is empiric risk?
- The probability that a disease will occur in a family based on the family history rather than theory.
- Used for complex multifactorial conditions (compare to Mendelian inheritance which can be determined theoretically).
How does the method by which we identify the genetic factors involved in a mendelian condition differ from that of a multifactorial condition?
With a Mendelian condition, you would analyse within a family, whereas for a multifactorial condition, you would analyse within a group of unrelated patients.
Define association.
The occurrence of two or more traits in a population that is more frequent than can be readily explained by chance.
What is an association study used for?
- To identify genetic factors involved in common conditions.
- To answer the question ‘do people with a condition share a particular DNA pattern?’.
- Compare SNPs between group of patients with the disease and a control group.
What is the International Hapmap project?
A project to map human DNA variants for researchers to use in finding genes predisposing to disease.
What is a single nucleotide polymorphism (SNP)?
A substitution of a single nucleotide that occurs at a specific position in the genome, where each variation is present to some appreciable degree within a population.
