GENE POLYMORPHISM AND PHARMACOGENOMICS Flashcards
what are Adverse Drug Reactions (ADRs)?
Unintended events that occurs at drug doses used in humans for prophylaxis, diagnosis, therapy or modification of physiological functions
what is precision medicine?
Influence of genetic variation on drug response in patients by correlating gene expression or presence of single-nucleotide polymorphisms (SNPs) with a drug’s efficacy or toxicity
what is DNA?
Paired double-stranded helical molecule capable of replicating and responsible for directing an organism’s inherited activities by directing the expression and composition/structure of cellular proteins
what are bases?
The basic chemical building blocks of DNA that determine its sequence
Adenine (A) Guanine (G) Thymine (T) Cytosine (C)
what are base pairs?
A single pair of complementary bases from opposite strands of the DNA double helix
A is always paired with T G is always paired with C
what is a gene?
A discrete unit of hereditary info consisting of a specific DNA sequence that carries the instructions to make specific proteins
what are non-coding regions?
Regions of the chromosome in-between genes
what is a chromosome?
Thread-like structure in the nucleus consisting mainly of a long DNA molecule comprising 50-300,000 base pairs which code for thousands of genes.
Humans each have 23 pairs of chromosomes
what is a genome?
An organism’s complete set of DNA
what is transcription?
generation of RNA from a DNA template. This is initially in the form of a primary transcript
what are exons?
blocks of a gene whose DNA sequence will ultimately determine AA sequence
what are introns?
blocks of a gene which do not code for protein and which are removed during the processing of primary transcript to generate mRNA
what is translation?
process in which protein is made using mRNA sequence as a template
what is a mutation?
A change in DNA sequence
what is a nonsynonymous mutation?
Mutation that ultimately results in a change in protein sequence
what is an allele?
One member of a number of different forms/variations of a gene
what is a genotype?
Combination of alleles for a given gene within an individual
An individual’s genotype is defined by the 2 alleles present [chromosomes are paired]
what is a SNP (single nucleotide polymorphism)?
DNA sequence variation when a single base differs at the same genetic location between different chromosomes
what is a haplotype?
Combination of SNPs present at different genetic locations that are transmitted together on the same chromatid (=replicating chromosome)
what are the benefits of precision medicine?
Advanced screening
Better drugs
Design/administration of “customised drugs”
Improved dosing regimens
Improved drug discovery and approval process
what causes variation in the human genome?
polymorphism
deletion
insertion
can variations cause no changes?
yes Most variations in the genome occur in noncoding regions and have no known effect
Some changes that occur in coding and regulatory regions also have no known effect
what are silent mutations?
variations that cause no changes or effect
can variations be harmful?
yes some variations in coding and regulatory regions have harmless effects
Influence benign individual characteristics Examples: Eye colour, Stature, Shape
what causes harmful variation?
Specific variations in coding and regulatory regions result in harmful effects
These changes alter function or expression of important proteins needed for health
what is haemophilia?
“simple” disease in which variation in ONE gene (Factor VIII)
causes disease
what are diabetes/heart diseases?
“complex” diseases. Symptoms seen only after many variations have occurred in different genes in the same cell
what are variations causing latent changes?
These coding region and regulatory variations are not harmful on their own
Changes only becomes apparent if they eventually cause some people to be at higher risk for disease only after exposure to environmental factors