Genetic Disease Flashcards
What is linkage?
The principal that genes which are close together tend not to get split apart
What are the 2 types of genetic disease?
- Germline
- Somatic
What are the types of germline disease?
- Chromosomal defects
- Monogenic disorders
- Polygenic disorders
What are the 3 ways prenatal testing can be carried out?
- Aminocentesis
- Chorionic Villus Sample
- Maternal Blood Test
How does aminocentesis work?
Aminotic fluid contains foetal cells which are cultured
What are the downsides to aminocentisis?
- only get 1 chance
- Increases risk of miscarriage
What is a chorionic villus sample?
Tissue that will make placenta is removed and analysed
What is the advantage of the chorionic villus sample?
It can be analysed more quickly than aminocentisis
What is the disadvantage of the chorionic villus sample?
It increases risk of miscarriage
What are the disadvantages of maternal blood test?
Currently not very accurate
How does a maternal blood test for prenatal testing work?
Foetal DNA can be detected in maternal blood, this can be used to detect trisomies
What are the 2 types of postnatal testing?
- Neonatal testing
- Adult testing
How is neonatal testing carried out?
Heel prick test
Give an example of a disease which is tested for by heel prick tests
Phenylketonuria
What is the advantage of neonatal testing?
It allows for fast intervention
Why is adult genetic testing done?
For carrier detection and for diagnosis of late onset disorders
What are the methods used for genetic testing?
- chromosome analysis
- molecular analysis
What can cause chromosomal defects?
- Abnormal separation
- Abnormal crossing over
What are the types of chromosomal defects?
- numerical
- structural
- chromosome translocation
What is turner syndrome?
When a woman has only one x chromosome
What is Klinefelter syndrome?
Men who have XXY chromosomes
What is reverse genetics?
Using the genotype to find the phenotype
How can the location of a gene responsible for causing a disease be found?
- Chromosomal defects
- Linkage analysis
How does linkage analysis occur?
Use markers to find differences between individual genomes
Give an example of a disease due to repeat expansions
Huntingdons disease
What methods are used for identifying genes involved in polygenic disorders?
- candidate genes
- linkage analysis
- association studies
What is mosaicism?
When a proportion of cells in the body carry a genetic defect
Are tumour suppressor genes dominant or recessive?
Recessive
Are oncogenes dominant or recessive?
Dominant
