revertant mutation – this term is used in two ways.
Firstly when referring to a genetic change that shows the virus is returning from a drug resistant mutation back to a wild-type genotype. This can sometimes take several stages. For example, T215E/D/E and S are revertant mutations that can indicate the drug resistant mutation T215Y is being replaced by wild-type (i.e. T215T).
It can also refer to the fitness of a virus. A revertant mutation can refer to an additional mutation that allows the virus to regain viral fitness (most drug mutations also make the vurs less fit). The second example is called a compensatory mutation as is compensates for the reduced fitness caused by the first mutation.
epoetin-alpha (EPO) – a treatment for anaemia, given by injection. Used to reduce side effect of hepatitis C treatment.
second-line therapy – the combination of used after your first treatment has failed.
genotype (or genotypic) – This term has several common uses:
1. a general term for the molecular structure of a living organism or virus.
2. a test that looks at the structure of an organism of virus (ie genotype resistance test looks for changes in the virus structure – called mutations).
3. a category for different types of similar viruses – ie hepatitis C has many subtypes, referred to as genotype-1, genotype-2 etc. HCV genotype is the strongest predictor of response to hepatitis C treatment.
See also phenotype.
lesion – damage to a part of the body.
