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Flashcards in Genetic Predisposition Deck (39):
1

Reduced penetrance

BRCA1/BRCA2 mutation (breast cancer)
-45-65% of women with this mutation develop breast cancer
-not all individiduals with the genotype will express the phenotype

2

What is variable expressivity?

-Marfan syndrome: variation of signs and symptoms:tall, thin and long fingers (life threatening complications in the heart and vessels)
-cardiovascular system (aorta sensitive to pressure, can't do extreme exercise) negatively affected

3

Do the same genetic disorders always display the same signs and symptoms?

Nah

4

polygenetic

disease caused by many genes

5

multifactorial

-environmental factors affect the likelihood of the disease

6

Mitochondrial gene mutations

the genes involved in mitochondrial disease normally make proteins that work inside the mitochondria (ATP production)
-if you have any kind of mutation, it affects ATP synthesis

7

Mitochondrial DNA

-can replicate on themselves, kind of behave like bacteria in our cells
-mitochondrial DNA can only be passed on from the mother (sperm do not contribute any mitochondria)
-children of a mother with a mitochondrial DNA mutation will be affected, with different degrees of severity (random)

8

Genetic predisposition

1. Mitochondrial gene mutations
2. genomic imprinting
3. impact of other genes (polygentic) and the influence of environment factors (multifactorial)

9

Genomic imprinting

the epigenetic phenomenon by which certain genes are expressed in a parent-of-origin-specific manner
-gene expressoin depends on DNA accessibility

10

DNA classifications

-DNA that is very packed is hard to read, and not availible, it cannot be accessed, we do not make this protein in this cell
-if the gene is so packed it cannot have an expression, it's like having a mutation
-DNA that is loosely packed

11

Imprinted

Packed
-gene expression depends on DNA accessibility
-Some genes are regulated depending on their paternal/maternal origin

12

Prader-Will syndrome

-weak muscles, poor feeding, slow development
-in childhood, constantly hungry, obesity/diabetes
-father's chromosome #15 is deleted

13

Angelman syndrome

-intelllectual and developmental disability, sleep disturbance, seizure, jerky movements
-mother's 15th chromosome is deleted

14

Identical twins - why don't they have the same diseases even with the same environmental factors

-1 twin expresses disease and one does not because of genetic imprinting

15

polygenetic and multifactorial disorders

-they are caused by the presence of particular combination of alleles at multiple genes

16

Skin color

-depends on how alleles are distrubuted and how many "light" or "dark" alleles are present

17

What does a person's position on liability distribution correlate to

the risk of showing disorder, severity and/or onset of diabetes

18

Is a lot of insulin a good thing?

Usually yes because it helps with the reuptake of glucose

19

genetic liability:

distribution of genes that contribute to a certain disease
-most people have a mixture of good and bad alleles
-there is a threshold for genetic liability

20

single nucleotide polymorphism (SNP) ;65 of them

depending on how many of the 65 indicate risk for diabetes, correlates with a high liklihood of getting diabetes

21

Who has a lower threshold for liabilities?

Males (males more likely to get diseases)
-need less of the "bad" alleles to inherit a disease

22

What increases the risk for getting polygenetic disorders?

1. more blood relatives are affected
2. affected relatives show more severe expressions
3. affected relatives of the same gender are more likely to be affected

23

Genetic factors for hypertension

-alleles involved with atrial natriuretic hormone (ANH) production
-alleles for the sodium transporters in the kidneys
-alleles for aldosterone

24

Lifestyle consideratoins

-toxin exposure
-diet
-activity
-sleep habits

25

Toxin exposure

ex: asbestos
-accumulates in the lungs, cannot be digested, causes chronic inflammation, increasing the liklihood of cell deaths and cancer

26

Diet

-nutritional deficiencies: diet restrictions, malabsorption disorder
-less-optimal nutrition intake
-too much : high fat, salt
too little: antioxidants, vitamins, trace minerals

27

Activity pattern

regular exercise is protective overall due to: metabolic alterations, remodeling, modulated stress response, signals that alter brain acitivity

28

Sleep habits

-sleeping less than 7 hours is associated with obesity
-

29

risk calculations

relative risk = incidence with factor/incidence without factor

30

Example of risk calculation

0.17% of heavy smokers die per yr of lung cancer/0.007% of nonsmokers die/year of lung cancer = 23.4
-Heavy smokers are 23 times more likely to die of lung cancer than nonsmokers

31

top to bottom on triangle

most to least predictable by pedigrees

32

left to right on triangle

less to more under the individual's control (polygenetic = less control, environment can sometimes be prevented)

33

teratogens

factors that cause congenital malformation - purely due to an environmental cause

34

What is thalidomide?

-was used to nausea, pregnant women used it, causes malformation in extremity development
-could also lead to unintentional abortions
-drug was never tested
-changed how we put drugs on the market

35

How long is the embryonic period?

Between 3 and 9 weeks
-most vulnerable time
-many women do not know they are pregnant at this time

36

Teratogenic agents

1. chemicals and drugs
2. infectious agents
3. radiation

37

Examples of chemicals and drugs

-thalidomide
-alcohol

38

Examples of infectious agents

-rubella
-zika virus (cause microcephaly)

39

Examples of radiation

atomic bomb
woman going through radiation therapy
-impact on brain development
-anatomical malformations
-increased cancer risks