Human Genetics Flashcards
0
Q
Accepted model of tumorigenesis
A
- multi step and multigene somatic mutations occurring in key regulatory genes
- most tumours contain mixed population of cells (reflect evolutionary development of the tumour in the body)
1
Q
3 major classes of gene involved in cell cycle control and tumorigenesis
A
- proto-oncogenes
- tumour suppressor genes
- DNA repair genes
2
Q
Definition of single gene disorders
A
- mutation occurs at a single locus and is sufficiently severe to cause disease
3
Q
Types of single gene disorders
A
- autosomal dominant
- autosomal recessive
- X-linked recessive
4
Q
Possible characteristics for AD inheritance
A
Non-penetrance
- some individuals who are affected at genotype level are not clinically affected (phenotype level)
Variable expressivity
- if phenotype clinically affected, may be of variable severity
5
Q
Characteristics of mutations in multi factorial disease
A
- do not cause severe dysfunction to the protein product (enzyme or receptor)
- typically cause mild change in function
6
Q
How mutations in MDs do affect the disease
A
- most genes function in groups
- mutations may cause similar effects in several genes with related functions
- together, these effects may be sufficient to cause disease (esp if there’s a predisposing environmental factor
7
Q
Recurrence risk increases with:
A
- frequency in the population
- number of affected relatives (esp,FDR)
- age of onset of affected relatives
- predisposing environmental factors
8
Q
When do you suspect hereditary development of breast cancer?
A
- pedigree suggests AD inheritance
- early onset
- multifocal/bilateral
- male breast cancer
- ovarian cancer
9
Q
In which populations is the BRCA mutation common?
A
- Afrikaners
- Ashkenazi Jews
- Icelanders
