Identifying individuals who are at increased risk of adverse drug reactions with drugs that are metabolized by UGT1A1; especially irinotecan, but also including atazanavir, nilotinib, pazopanib, and belinostat
Identifying individuals with Gilbert syndrome due to the presence of homozygous UGT1A1*6 (c.211G->A) allele, TA7, homozygous TA8, or compound heterozygous *6, TA7 or TA8
Identifying individuals who are carriers of Gilbert syndrome due to the presence of heterozygous TA7 or TA8
This pharmacogenomic test interrogates the thymine-adenine (TA) repeat in the TATA-box of the promoter region of UGT1A1. Repeat number may vary from 5 to 8 TA repeats, with 6 TA repeats representing the most common (normal) number of repeats. Individuals with more than 6 TA repeats may have an increased risk for adverse drug reactions to drugs metabolized by UGT1A1, especially atazanavir, irinotecan, nilotinib, pazopanib, and belinostat. Homozygosity for TA7, TA8, or compound heterozygosity for TA7/TA8 is also consistent with a diagnosis of Gilbert syndrome. Heterozygosity for TA7 or TA8 is consistent with carrier status for Gilbert syndrome. Note that this testing uses a tagging single nucleotide polymorphism (SNP) strategy for the TA5 and for the TA7 and TA8 repeats. This testing is not able to distinguish between TA7 and TA8 so when the tagging SNP is detected, TA7 is assigned. The function of genes with TA7 and TA8 repeats are thought to be the same. In addition, this test evaluates the UGT1A1*6 (c.211G->A) allele.
