Genetics Flashcards
What is penetrance?
Likelihood of having a disease if you have a gene mutation
What pattern of inheritance do Mendelian disorders follow and describe what this is?
- Mendel’s Laws
- disease predominantly caused by single gene change so is high penetrance
What genetic test used for seeing whole genome?
Next generation sequencing
How does NGS work?
Breaking up genome and then sequencing genes and comparing to standard sample
What are 3 things mutation could be?
- Disease causing mutation
- Polymorphism
- Variant of unknown significance
Genetic variant means pathogenic. True or false?
False
What is a polymorphism?
- Variant that is prevalent in the general population
- often implies benign or may have low penetrance effect on common disease
Cystic fibrosis, neurofibromatosis and Marfan’s syndrome are all examples of what type of disorder?
Mendelian disorder
What 5 questions help differentiate between pathogenic mutation or polymorphism?
- is it in coding bit of gene
- does it affect gene e.g. change lysine to stop codon
- exclude ones we know are polymorphisms
- is it in a gene that causes the disease
- does it match pattern of inheritance
What are 5 classifications of variant?
1: definitely benign
2: probably benign (90%+)
3: variant of uncertain significance
4: probably pathogenic (90%+)
5: definitely pathogenic
How is causative variant found from 3,000,000 variations?
Filtered
E.g. right genes, ones that affect gene (stop/frame shifts etc), not listed as polymorphisms
What is coding part of gene called?
Exon
What does DNA undergo to become mRNA?
Transcription and splicing
What is splicing?
Removing non-coding regions called introns
What process does mRNA undergo to form a protein?
Translation
