Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

IMMS > Inheritance > Flashcards

Inheritance Flashcards

1
Q

What is a multifactorial condition

A

Disease that is due to a combination of genetic and environmental factors

Most common diseases are multifactorial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are family studies

A

Compare the incidence of a disease amongst relatives of an affected individual with the general population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Family Studies

With risk for a multifactorial condition - fill in the gaps

  1. The risk of a condition in relatives of an affected individual is than the general population
A

Dramatically higher

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does proband mean

A

Individual affected with a disorder who is the first subject in a study (as of a genetic character in a family lineage)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the three ways of studying if a condition
has a genetic component

A

Family studies
Twin studies
Adoption studies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does prevalence mean

A

How common a disease is in a given population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does incidence mean

A

Onset of new cases in a given period of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are twin studies?

A

Compare genetically identical (MZ) with genetically non-identical (DZ) twins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does concordance rate stand for?

A

% of twin pairs studies that both have the condition

Would expect it to be higher in monozygotic twins

Gives a rough figure for hereditability of a multifactorial disorder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are adoption studies?

A

Adopted children of a parent with multifactorial condition have a higher risk of developing the disease

Higher in biological families only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Define hereditability

A

Proportion of the aetiology that can be ascribed to genetic factors as opposed to environmental factors

Expressed as a proportion of 1 or as a %

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a way you can calculate hereditability

A

Concordance rate in monozygotic twins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Name the three characteristics of multifactorial inheritance

A
  1. The incidence of the condition is greatest amongst relatives of the most severely affected patients
  2. The risk is greatest for the first degree relatives and decreases rapidly in more distant relatives
  3. If there is more than one affected close relative then the risk for other relatives are increased
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define liability

A

When combine factors that influence the development of a multifactorial disorder, genetic and environmental

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

In the liability/threshold model which direction is the curve shifted in relatives compared to the normal population

A

Right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

When the relationship is closer which direction does the curve shift in the liability/threshold model

A

Further to the right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the threshold marker in the liability/threshold model

A

Beyond this the abnormal phenotype is expressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the definition for in the general population the proportion beyond the threshold (in the liability threshold model)

A

Population incidence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the definition for amongst relatives the proportion beyond the threshold (in the liability threshold model)

A

Familial incidence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the genome wide association studies

A

Utilises the fact genes can have several variants (alleles)

Compares the frequency of markers in a sample of patients and a sample of healthy controls

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What would a pathogenic variation of a disease be

A

Variation in a gene which causes the gene to be inactivated or behave abnormally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Define polymorphisms

A

Genetic variation which still results in a functioning gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the 4 environmental agents acting on embryogenesis

A
  1. Drugs and chemicals
  2. Maternal infections
  3. Physical agents
  4. Maternal illnesses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Name 4 post-natal environmental factors

A
  1. Type 2 diabetes - obesity
  2. Breast cancer - hormonal factors e.g. contraception
  3. Lung cancer e.g. smoking
  4. Schizophrenia e.g. recreational drugs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the 3 underlying principles of genetics are deduced by Mendel

A
  1. Segregation
  2. Dominance
  3. Independent assortment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the two types of mendelian inheritance

A
  1. Autosomal and sex-linked
  2. Dominant and recessive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are the four types of non-mendelian inheritance

A
  1. Imprinting
  2. Mitochondrial inheritance
  3. Multifactorial
  4. Mosaicism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are the three categories of genetic disorders

A
  1. Chromosome abnormalities
  2. Single gene disorders
  3. Multi-factorial and polygenic disorders
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Define autosome

A

Any chromosome, other than sex chromosomes, that occurs in pairs in diploid cells

30
Q

Define recessive

A

Manifest only in homozygotes

31
Q

Define allele

A

One or more alternative forms of a gene at a given location (locus)

32
Q

Define homozygous

A

Presence of identical alleles at a given locus

Homozygotes are affected

33
Q

Define heterozygous

A

Presence of two different alleles at a given locus

Heterozygotes are unaffected and are usually referred to as carriers

34
Q

Define allelic heterogeneity

A

Different mutations within the same gene result in the same clinical condition

35
Q

What are the three typical features of autosomal recessive inheritance

A

Male and females are affected on equal proportions

Affect individuals only in a single generation

Parents can be related (consanguineous)

36
Q

How can you calculate risk of carriers

A

Chance mother is a carrier x chance dad is carrier x risk of affected child if both carriers

Use population carrier frequency if risk is that of normal

37
Q

Define consanguinity

A

Reproductive union between two relatives

38
Q

Define autozygosity

A

Homozygosity by descent

e.g. inheritance of the same altered allele through two branches of the same family

39
Q

In autosomal recessive conditions what are the chance of carrier parents having affected offspring

What are the chances of healthy siblings being carriers themselves

A

1 in 4

2 in 3

40
Q

Define autosomal dominant inheritance

A

Disease manifest in the heterozygous state e.g. only one affected gene needed

41
Q

What are the 3 typical features of autosomal dominant inheritance

A
  1. Males and females are affected in equal proportions
  2. Affected individuals are seem in multiple generations
  3. Transmission by individuals of both sexes, to both sexes
42
Q

Define penetrance

A

The percentage of individuals with a specific genotype showing the expected phenotype

43
Q

Define expressivity

A

Refers to the range of phenotypes expressed by a specific genotype

44
Q

In autosomal dominant inheritance what is the recurrence risk

A

50% for transmission of the mutation

Dependant on penetrance and expression

45
Q

Define anticipation

A

Genetic disorder affects successive generations earlier or more severely, usually due to expansion of unstable triplet repeat sequences

46
Q

Define somatic mosaicism

A

Genetic fault present in only some tissues in the body

47
Q

Define gonadal (germline) mosaicism

A

Genetic fault present in gonadal tissue

48
Q

Define late-onset

A

Condition not manifest at birth (congenital), classically adult-onset

49
Q

Define sex-limited

A

Condition inherited in the autosomal dominant pattern that seems to affect one sex more than another

50
Q

Define predictive testing

A

Testing for a condition in a pre-symptomatic individual to predict their chance of developing a condition

51
Q

What is the only mode of transmission where male to male transmission is seen?

A

Autosomal inheritance

52
Q

Define x-linked inheritance

A

Genes carriers on the X chromosome

53
Q

What are the three typical features of X-linked inheritance

A
  1. Usually only male affected
  2. Transmitted (usually) through unaffected females
    - Female carriers can be affected to lesser degree
  3. No male-male transmission
54
Q

Define lyonization (X inactivation)

A

Generally only one of two X chromosomes active in each female cell. Can be skewed

55
Q

Can an infected male in X-linked inheritance have an affected son

A

An affected male cannot have an affected son

But all daughters will be carriers

56
Q

Define genomic imprinting

A

Epigenetic phenomenon that causes genes to be expressed in a parent-of-origin-specific manner

57
Q

Define epigenetic

A

Non-genetic influence on gene expression

58
Q

Define homoplasmy

A

A eukaryotic cell whose copies of mitochondrial DNA are all identical (identically normal or have identical mutations)

59
Q

Define heteroplasmy

A

Multiple copies of mtDNA in each cell

Can vary between cells in the same tissue or organ and organ to organ in the same person and between individuals of the same family

60
Q

What are the 4 factors of mitochondrial genetic disease

A

Group of disorders caused by dysfunctional mitochondria

Caused by mutations in the mitochondrial DNA (15%)

Caused by mutations in nuclear genes, whose gene products are imported into the mitochondria

Acquired conditions caused

61
Q

What is the carrier frequency of sickle cell disease (haemochromatosis)

A

1/10

62
Q

What is the carrier frequency of cystic fibrosis

A

1/25

63
Q

Name some autosomal recessive conditions

A

Haemochromatosis (sickle cell disease)

Cystic fibrosis

Congenital adrenal hyperplasia

Connexin-26 (deafness)

Tay-Sachs disease

MCAD disease

Spinal muscular atrophy

Friedreich’s ataxia

Hurler syndrome

Ataxia telangiectasia

64
Q

Describe cystic fibrosis

A

Commonest AR condition affecting northern European population

Chronic condition mainly affecting lungs and guts - variable presentation

Incidence - 1 in 2500

CFTR gene on 7q31.2

F508 commonest mutation (80%)

65
Q

What is the sweat test

A

Diagnostic test for cystic fibrosis

Not genetic marker

66
Q

If someone in a parents genetic line has an autosomal condition what is the equation for risk to there child (if neither have been tested)

A

Parent with genetic line = 1/2 (chance a carrier)

Parent b = 1/25 (population carrier frequency)

Risk of affected child if both carriers = 1/4

1/2 x 1/25 x 1/4 = 1/200

67
Q

Autosomal recessive

One parent + one parent - equation

A

Chance parent a = 1
chance parent b = 1/250 (test only detects 90% mutations)

risk of affected child if both carriers = 1/4

1/1000

68
Q

What is the phenotype correlation in cystic fibrosis of genotype F508

A

Pancreatic insufficiency and chronic lung disease

69
Q

What is the phenotype correlation in cystic fibrosis of genotype R117H

A

Majority are pancreatic sufficient but have chronic lung disease

70
Q

What is an example of x-linked inheritance

A

Haemophilia

71
Q

What is an example of multifactorial inheritance

A

Cleft lip and palate

Combination of both genetic and environmental factors

IMMS (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions