Prevalence of UGT1A1 Genetic Variants in Argentinean Population, Potential Implications for Pharmacogenomic Testing

ABSTRACT The four groups of uridine diphosphate glucuronosyltransferase (UGT) enzymes form a superfamily responsible for the glucuronidation of target substrates. These include hormones, flavonoids, environmental mutagens and pharmaceutical drugs. Thus, UGT enzymes are relevant for pharmacogenetic research. Most of the members of the UGT family are expressed in the liver, but are also present in intestinal, stomach or breast tissue. The incidences and types of polymorphisms for different enzymes vary with geographical regions and ethnic groups. This is the first study that examined the frequency of polymorphisms for UGT1 isozymes for a population of 100 healthy argentinians. The distribution of UGT1A1 in our population was: 70.5% (70.5) for the *1 allele, 21.5% for the *28 allele and 1% for the *36 allele. 48% (48) presented the *1/*1 genotype, while 43 % (43) had *1/*28, 2% (2) had *1/*36 and 7% (7) showed *28/*28. There was no preferential sex distribution. Since most Argentinians are of Caucasian descent, a European genotype frequency profile is to be expected. That is evident in the wild type prevalence in our population. However, the contribution of Native American ancestry to gene pool components may in part explain the higher prevalence of the *28 genotype in UGT1A1 *1 in our population, in comparison with European cohorts.