Week 1 GID

Question 1

Is stroke genetic or enviromental cause or both.

Answer 1

multifactorial with environment and polygenic factors. Sometimes can be caused by a single gene influence (Cadasil)

Question 2

The traits of a genetic disorder

Answer 2

Rare, Genetics simple, Unifactorial, High recurrence rate: high chance of others to have disorder

Question 3

The traits of enviromental disorder

Answer 3

Common, Genetically complex, multifactorial, low recurrence rate,

Question 4

What does multifatorial mean

Answer 4

The combination of multiple gene inheritance and the affect of the enviroment

Question 5

What is single gene mutation

Answer 5

mutation in a single gene

Question 6

Chromosomal mutation

Answer 6

imbalance or rearrangement in chromosome structure eg aneuploidy, deletion, translocation

Question 7

Mitochondrial

Answer 7

mutation in mitochondrial DNA

Question 8

Somatic mutation

Answer 8

Mutation that occur in the general genes and can cause cancer

Question 9

Does AD inhertiance run between generation and does it affect males or females more?

Answer 9

runs between generations and affects males and females equally

Question 10

% chance of inheritance of AD disease

Answer 10

50% chance of inhertiance for new born

Question 11

Give examples of AD inhertiance disease

Answer 11

Myotonic dystrophy
Marfan Syndrome
Huntington disease

Question 12

What does penetrance mean?

Answer 12

The frequency with which a specific genotype is expressed by those individuals that possess it, usually given as a percentage.

Question 13

What is incomplete inheritance and give example of mutation of this type?

Answer 13

not all relatives who inherit the mutation develop the disorder – eg BRCA1 mutations 80% life time chance of developing breast cancer

Question 14

What type of inheritance is AD

Answer 14

incomplete inheritance

Question 15

What does expressivity mean?

Answer 15

variation in expression - the extent to which a heritable trait is manifested by an individual.  how the disease shows itself

Question 16

What does Anticipation mean and give example

Answer 16

the symptoms of a genetic disorder become apparent at an earlier age as it is passed from one generation to the next. In most cases there is an increase in the severity of symptoms too. Example is Huntington’s disease

Question 17

New mutation/ De novo

Answer 17

a new mutation that has occurred during gametogenesis or in early embryonic development. The parents do not have it

Question 18

Is Ar disease passed on between generations and equal between genders

Answer 18

Usually only seen in one generation and equal in affect

Question 19

Is Ar inheritance gene mutation or chromosomal deletion

Answer 19

gene mutation

Question 20

What is the chance of inheriting a Ar disease

Answer 20

1/4

Question 21

Risk of the unbrone child being a carrier of Ar diseae

Answer 21

2/3rds

Question 22

Give examples of Ar diseases

Answer 22

• Cystic fibrosis
• Many of the metabolic disorders
• Haemachromatosis
• Sickle cell disease

Question 23

In X linked disease is the male or female affected

Answer 23

Male are affected but females can be mildly affected ranging to severe symtpoms

Question 24

Can or cant a male transmit the XL disease and why?

Answer 24

It cannot because males only give the Y chromsome and therefore only transmit from the female

Question 25

give examples of XL diseases

Answer 25

o Duchenne Muscular dystrophy, o Fragile X syndrome o Red / green colour-blindness o Haemophilia

Question 26

What are the probablities for the child if the mother is a carrier

Answer 26

o 1/4 (25%) normal girl + 1/4 (25%) carrier girl | o 1/4 (25%) normal boy + 1/4 (25%) affected boy

Question 27

Probablity if the father is affected

Answer 27

o All daughters are carriers | o All sons are unaffected (no male to male transmission

Question 28

The two main factors that affect the expression of the phenotype of XL disease in females is

Answer 28

X inactivation | XL dominant vs XL recessive inheritance

Question 29

Can you predict the phenotype of a female who havea XL disease with prenatal testing?

Answer 29

NO

Question 30

What is X inactivation

Answer 30

It is when the gamete has two X chromosomes and one of the X chrosome is randomly switched off. Occurs in embryogensis

Question 31

Examples of Xl dominant disease

Answer 31

o Rett syndrome (lethal in males, phenotype only in females) | o Fragile X syndrome – females:- asymptomatic to fully symptomatic ( due to X-inactivation pattern)

Question 32

Examples of Xl recessive disease

Answer 32

o Red-green colour blindness o Haemophilia o Duchene Muscular dystrophy o Carrier girls usually unaffected BUT can have significant symptoms because of X-inactivation (switches off normal X) o Girls fully affected if inherit mutation from mum and dad

Question 33

Is mitchondrial inheritance maternal or paternal inherited and why?

Answer 33

It is maternally inherited because the sperm has no mitochondria so all comes from the mother

Question 34

how many genes within the mitchondrial DNA

Answer 34

27

Question 35

Give exampes of non genetic testing

Answer 35

Blood testing --> enzyme assasys Haemotology--> thalasemia X Rays

Question 36

Examples of genetic testing

Answer 36

o Genomic architecture --> Cytogenetics | o Sequencing --> OLA assays + MLPA tests

Question 37

What does Pharmacogenomics mean?

Answer 37

Analysing entire genomes, across groups of individuals, to identify the genetic factors influencing responses to a drug.

Question 38

What does Pharmacogenetics mean?

Answer 38

Studying an individual's genetic make up in order to predict responses to a drug and guide prescription

Question 39

What is Chronic myeloid leukemia ?

Answer 39

It is the translocation of a part of chromosome 9 with 22. Causing the over production of WBC

Question 40

What is the name of the chromsome that caries the BCR/abl gene of CML

Answer 40

Philadelphia chromosome

Question 41

What treatment is given to treat CML

Answer 41

Glevec

Question 42

what test do you do if you already know the identity of the mutation?

Answer 42

simple and cheap analytical methods --> robust assay

Question 43

What tests do you do if you don't know the identity of the mutation?

Answer 43

You do clonal sequencing and discovery methods ( Sanger DNA sequences)

Question 44

What enzyme is used to add nucleotides in DNA replication/sequencing

Answer 44

DNA polymerase

Question 45

Go through the process of PCR

Answer 45

Heat too 97 degrees to denature and sepearte the DNA strand. Then cool down to 50 degrees for annealing and allow the adding of primers Then heat slightly too 72 degrees for the addition of nucleotides --> DNA poylmerization can occur

Question 46

Give examples of what PCR can be used for?

Answer 46

Identifity genetic finger prints DNA sequences Isolation of specific DNA strands

Question 47

Why do DNA move through the gel electrophersis

Answer 47

Because they are negatively charged due to the phosphate backbone

Question 48

What is the factor that causes the different movement of DNA strands

Answer 48

The size of teh DNA strand

Question 49

What is allele specific PCR used for

Answer 49

For the absense or presence of product

Question 50

What is the common mutation in CF

Answer 50

3 base pair deletion --> elimination of a single aa

Question 51

what is the most common inherited cause of deafiness

Answer 51

connexin 26

Question 52

What is connexin 26

Answer 52

1 base pari deletion --> nucleotide 35

Question 53

what is Allele specific mutation detection ?

Answer 53

Process by distinguishing from two different alleles that may only have a single diference in one base

Question 54

What information does the CF genotype assay is used for?

Answer 54

carrier screening in adults in reporductive age aind in new born screeing used in testing new borns and children

Question 55

What is Cf genotype assay not used in?

Answer 55

Pre implantation testing and fetal diagnostic

Question 56

Why might the tempalte be unsuitable for PCR

Answer 56

To big for the PCr Fragile X syndrome FMR1 gene has repetitive tract of (CGG)n sequence Have to many GC rich regions

Question 57

What technique is used for unsuitable templates for PCr

Answer 57

Southern blotting

Question 58

what technique do you use for identifying unknown mutation and what is the pros

Answer 58

DNA sequence --> find the exact postion of the mutation and what type of mutation it is

Question 59

For DNA sequencing what do you need for the addition of nucleotides

Answer 59

Free hydroxl group on the 3 end

Question 60

What direction is DNA sequencing ?

Answer 60

5 to 3 direction

Question 61

What DNA is sequenced by clonal sequencing?

Answer 61

Exome panels --> only exons of the gene

Question 62

Why do DNA testing

Answer 62

confirm or refute clinical diagnosis, prenatal testing, assess carrier status and for predicting testing