Definitions of common pharmacogenetic terms

 
Definitions of Pharmacogenetic Terms

Allele

Alternate form of a gene located on a specific chromosome

Chromosome

Linear bodies in the cell nucleus containing most or all genes of the organism

Deletion

Absence of a section of genetic material from a gene or absence of 1 or more entire genes from a chromosome

Duplication

Part of a chromosome in which the genetic material, including an entire gene or genes, is repeated; or process of forming a duplication

Expression

Detectable effect of a gene, usually manifested by the amount and/or type of protein

Gene

Functional unit of heredity occupying a specific locus on a chromosome; capable of reproducing itself exactly at each cell division; directs formation of an enzyme or other protein

Genotype

Genetic constitution of an individual gene; may reflect a single nucleotide polymorphism, mutation, or series of variants

Haplotype

Group of genetic variants from 1 or more genes (eg, of the major histocompatibility complex) located on a single chromosome; usually closely enough linked to be inherited as a unit or characteristic pattern

Heterozygote

2 genes at corresponding loci on homologous chromosomes different for 1 or more loci; 2 different copies

Homozygote

2 genes at corresponding loci on homologous chromosomes identical for 1 or more loci; 2 identical copies

Insertion

Section of genetic material inserted into an existing gene sequence

Linkage

Relationship between genes on the same chromosome that causes them to be inherited together

Metabolizers

Poor metabolizer – lacks capacity (partially or almost totally) to metabolize a substrate through a specific pathway
Intermediate metabolizer – has less than normal capacity to metabolize a substrate through a specific pathway
Ultrarapid metabolizer – has enhanced capacity to metabolize a substrate through a specific pathway
Extensive metabolizer – has normal population-based capacity to metabolize a substrate through a specific pathway

Mutant

Change in hereditary material involving either a physical change in chromosome relations or a biochemical change in the codons that make up genes that are associated with a phenotype

Pharmacokinetics Study of how a patient's body processes a drug based on genetics  (eg, metabolic activation or inactivation of a drug)
Pharmacodynamics The response of the body to a drug (eg, positive vs. negative response)

Phenotype

Observable properties of an organism that are produced by the interaction between the genotype and environment

Single nucleotide polymorphism

Naturally occurring substitution of a single nucleotide at a given location in the genome of an organism, often resulting in phenotypic variability

Variant

Exhibiting variation or diversity, either genotypically or phenotypically

Wild type

Phenotype, genotype, or gene that predominates in a natural population of organisms or strain of organisms in contrast to that of mutant forms