human genetics 2 (disorders) Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

overall facts

A
  • 5,000 human disorders are known to have genetic origins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

recessive gene + single dominant gene

A

RG: PKU, sickle-cell anemia, tay sachs, cystic fibrosis
SDG: Huntington’s disease, neurfibromatosis

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

polygenic inheritance +sex-linked inheritance

A

PI: cancer, heart disease, asthma, psychiatric, behvaior disorders
SLI: red-green colour blindness, fragile-X syndrome

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

regulator gene defects, chromosomal abnormalities

A

RGD: genetic male with female genatalia
CA: downsyndrome, Klinefelter syndrome, turner syndrome

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

Tay- Sachs disease

A
  • fatal, autosomal recessive neurodegenerative disease of infancy and early childhood
  • gene tells the body to stop producing Hex-a enzyme needed to break down fatty subsance
  • caused by mutations of Hex A gene chromosome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Huntington’s disease

A

progressive neurodegenerative disorder, autosimal dominate.
>40 repreats of cytosine, adenine and guanine in coding region of gene
- onset= 4oy/o 12-15 yrs afterwards= death

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

symptoms of HD

A

cognitive deterioration, personality change, memory loss, depression, slow movement

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

invoulantary movement characteristic of HD

A

invoulantary ‘dance like’ movement
- abates in advance stages of disease, when akinetic and bradykinetic movements become clear

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

voulantary characterise movement in HD

A
  • Bradykinetic
  • inconsistent and inefficient movement
  • abnormal co-contractions of muscles
  • prolonged EMG bursts
  • less efficient and more variable movements in handwriting
  • sequential and simultaneous movement difficulties
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

broad sub-cortical and cortical damage

A
  • neuronal and astrocyte loss in basal ganglia
  • selective degeneration of GABAergic neurons of striatum
  • as disease progresses, greater cortical atrophy occurs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

HD cont.

A
  • gene contains expanded trinucleotide repeat that ranged from 9-35 in healthy adults but 36-190 for HD
  • allels with 36-39 repeat how ‘reduced penetrance’- only some individuals will develop clinical symptoms
  • young patiesnts= >55 repeats and develop HD before 20 y/o
  • onset earlier if transmitted by father
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

polygenetic inheritance

A
  • when traits are governed than more than one gene
  • shifts from focusing on single gene mutation to examining the combination of many genes working together
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

schizo

A
  • young adulthood= onset
  • 0.5% pop affected, can be continuous or episodic
  • more likley to be continuous than categorical
  • genetic risk of schizo= largely polygenenic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

fragile X syndrome

A
  • FXS= most common intellectual diability
  • expansion mutation of CGG repeat sequence in the FMR1 gene at the locus
  • leads to the silencing of the gene and absence of the gene product
  • protein is essential for brain development- brain synaptic plasticity, development
  • boys= more affected than girls
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Phenylketonuria

A
  • children w PKU are unable to metabolize phenylalanine
  • phenylalanine is a amino acid found in high protein food
  • PKU is a disorder that is related to a defective gene on chromosome 12, which the body cannot break down and may cause damages w brain development
  • early diagnosis= restricted diet can stop menta retardation.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

phenotype and genotype

A
  • development will only occur if a given gene is turned on and off at the correct time, in the right place and for the right length of time
  • some genes are only turned on in a few cells and for only a few hours and then switched off permanently
  • other genes= basic functioning of almost all cells
    regulator genes control the switching on switching off of genes
15
Q

phenotype acnd genotype

A

external factors= can affect the switching on and off of genes
- there is a continuous interaction between the environment and the genotype

15
Q

the range (norm) of reaction

A

refers to all the phenotypes that could theoretically result from a given genotype, given all the envuronemnts in which it would survive and develop

16
Q

range of norm- plants

A

three cuttings (genetically identical) taken from 7 plants, planted at different elevations.
- the phenotype is the unique consequence of a particular genotype in a particular environemnt

17
Q

phenotype and genotype

A
  • a child with a given genotype develops differently in a loving gamily compared to abusive
  • the child actively creates and explores the environment where they live
  • by virtue of nature, they evoke different responses
18
Q

epigenetics

A
19
Q

genome

A

recors of the genetic material of an organism encoded in DNA

20
Q

epigenome

A

record of the chemical changes to the DNA and histone proteins of an organism

21
Q

heritable

A

but reversible changes in gene expression that are not coded in the DNA sequence but by post-translational modifications in DNA< histone proteins are in micro RNA

22
Q

autoimmune disorders

A

they affect 7% of the population, it is not completely genetic so there is a role in the environment because some twins will have the disease while others wont.
- more females are affected than males and more likely away from equator.