2K- Multifactorial Inheritance

Question 1

What is a Multifactorial trait?

Answer 1

Polygenic (the combined effects of multiple genes) trait in which the environment also plays a factor

Question 2

What is the Threshold of liability?

Answer 2

the point on a liability distribution which has to be crossed in order to express the disease. The lower the threshold, the fewer alleles or environmental factors are needed to develop the disease

Question 3

What is the Recurrence risk?

Answer 3

The probability that another affected offspring will be produced in a family in which one or more of the children have already been affected

Question 4

What is a Concordant/discordant trait?

Answer 4

If both twins share a trait, they are concordant, if they do not share the trait they are discordant.

Question 5

What is Heritability?

Answer 5

Heritability is the % of population variation in a trait that is due to genes

Question 6

Is the recurrance risk higher or lower if more and 1 family memeber is affected?

Answer 6

higher

Question 7

What is a proband?

Answer 7

the first person in a pedigree to be identified with the disease

Question 8

If the expression of the disease in the proband is more severe, is the recurrence risk higher or lower?

Answer 8

Higher

Question 9

What are the origins of differences between monozygotic twins?

Answer 9

environmental.

Question 10

What is it called when both twins share a trait?

Answer 10

concordance

Question 11

What are Phenocopies?

Answer 11

people who have a phenotype but do not carry the known disease-causing mutation.

Question 12

What are QTL’s?

Answer 12

Quantitative trait loci are stretches of DNA containing or linked to the genes that underlie a quantitative trait.

Question 13

What is a Genome scan used for?

Answer 13

Markers from the entire human genome are tested for linkage with a disease phenotype.

Question 14

What is the Affected sib-pair method?

Answer 14

If two siblings are both affected by a genetic disease, we would expect to see increased sharing of marker alleles in the genomic region that contains a susceptibility gene

Question 15

What is the relationship between the LDL receptor and familial hypercholesterolemia?

Answer 15

it is mutated

Question 16

What is the genotype of familial hypercholesterolemia?

Answer 16

Autosomal dominant

Question 17

What is cardiomyopathy?

Answer 17

Abnormality of the heart muscle that leads to inadequate cardiac function

Question 18

What is mutated to cause cardiomyopathy?

Answer 18

Most commonly mutated genes are those that encode the β-heavy chain, myosin-binding protein C and troponin T

Question 19

What is dilated cardiomyopathy?

Answer 19

Increased size and impaired contraction of the ventricle causing impaired pumping of the heart.

Question 20

What is the genotype to cause dilated cardiomyopathy?

Answer 20

It can be autosomal dominant, X-linked or mitochondria

Question 21

What is the long QT syndrome?

Answer 21

Prolonged cardiac repolarization via blocking potassium channel.

Question 22

What genetic mutations can cause strokes?

Answer 22

Consequence of several single gene disorder, inherited deficiencies of protein C and S (coagulation inhibitor), mutation in clotting factor V.

Question 23

What genetic mutations can cause HTN?

Answer 23

Gene that encodes angiotensinogen

Question 24

What is MODY?

Answer 24

maturity onset diabetes of the young (MODY): Decreased insulin secretion. Occurs before 25 years of age

Question 25

What is the genotype to cause MODY?

Answer 25

autosomal dominant

Question 26

What accounts for 50% of the genetic mutations cause of MODY?

Answer 26

50% caused by mutations in the gene the encodes glucokinase (rate limiting enzyme in the conversion of glucose to glucose 6-phoshate in pancreas)

Question 27

What genetic mutations can cause Alzheimers?

Answer 27

Half of the early onset of AD is attributed to mutation in any of three genes that affect amyloid-β deposition. (PS1, PS2 & APP)

Question 28

What genetic mutations can cause obesity?

Answer 28

Genes and gene products involved in appetite control and susceptibility to obesity including leptin and its receptor.

Question 29

What genetic mutations can prevent alcoholism?

Answer 29

Having ALDH2 gene prevents you from becoming an alcoholic. (lol asians)

Question 30

What genetic mutations can cause schizophrenia and bipolarism?

Answer 30

Genes that encode neurotransmitters, receptors and neurotransmitter-related enzymes.

Question 31

What genetic mutations can cause ALS?

Answer 31

Superoxide dismutase 1