The enzyme UGT1A1 is part of the group of uridine diphosphate-glucuronosyltransferases (UGTs) and is involved in the conversion of fat-soluble substances, such as bilirubin, hormones and drugs, into water-soluble substances that can be excreted from the body. The toxic waste product bilirubin is converted in the liver only by the enzyme UGT1A1.
Drugs that can be metabolised by the enzyme UGT1A1 include:
- Cytostatics, such as irinotecan and etoposide
- Other drugs, such as atazanavir (antiretroviral) and raloxifene (oestrogen receptor modulator)
The activity of the enzyme UGT1A1 varies from one individual to another. As a result, the efficacy of a drug can differ from person to person, as can the potential side effects. This variation can be partly explained by genetic variations in the UGT1A1 gene.
When a genotype is determined these variations in the UGT1A1 gene are indicated by two so-called alleles. Each allele has a name consisting of an asterisk and a number. An example of a possible UGT1A1 genotype is UGT1A1*1*28.
At iGene we determine the following variants (alleles) of the UGT1A1 gene:
UGT1A1*6, UGT1A1*27, UGT1A1*28 (via UGT1A1*80) and other (classified as UGT1A1*1).