Genetics of Complex Diseases

Question 1

Define a single gene mutation

Answer 1

Mutation in a gene which is rare

Question 2

Define multifactorial mutations

Answer 2

1 gene affected

Question 3

Define chromosomal changed

Answer 3

100s of genes affected loss of chromsone function

Question 4

Define environmental factors

Answer 4

very common and includes viral and bacterial infections.

Question 5

Define mutlifactoral inheritance

Answer 5

The inheritance and expression of a phenotype being determined by the cumulative action of multiple genes at multiple loci.

Question 6

What is a monogenic disease

Answer 6

have a single strong penetrant phenotype

Question 7

What is a polygenic disease

Answer 7

Very common have lower penetrant phenotypes

Question 8

Define penetrance

Answer 8

Is the fraction of cases carrying a given gene that manifests in specified phenotype

Question 9

What 2 factors can cause penetrance

Answer 9

genetics

environments

Question 10

What is the liability threshold

Answer 10

measure of disease state of an individual

Question 11

Define heritability

Answer 11

The proportion of disease variation due to genetic variation.

Question 12

Define the difference between monozygotic twins and dizygotic twins

Answer 12

Monozygotic
single fetlizationg
genetically identical

Dizygotic
Independent fertilization events– Share approximately half their genes

Question 13

Define SNP

Answer 13

DNA sequence variations that occur when a single nucleotide (A,T,C,or G) in the genome sequence is alteredat the same genetic location between different chromosomes (either within an individual or between individuals)

Question 14

Define chromosome aneuploidy

Answer 14

Aneuploidy presence of an abnormal number of chromosomes in a cell