UGT1A1 Sequencing

Casandra

Casandra Test Code AR18777Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 3004386CPT Code 81404

Also known as: UGT1A1 NGS

Clinical Use

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Use

UGT1A1 sequencing is used to confirm the diagnosis of Gilbert syndrome or Crigler-Najjar syndrome, both of which are characterized by different levels of unconjugated hyperbilirubinemia. This test helps in identifying inherited nonhemolytic unconjugated hyperbilirubinemia related to UGT1A1 deficiency, which can lead to a spectrum of phenotypic expressions based on enzyme activity levels. It is also utilized in pharmacogenetic assessments, particularly when prescribing atazanavir to evaluate the probability of bilirubin-related discontinuation. Furthermore, it assists in dosage planning for patients undergoing high-dose irinotecan treatment.

Special Instructions

Informed consent is required for genetic testing, especially for patients from New York state. Both a Patient History Form and Informed Consent are necessary submissions for New York clients. Stability requirements indicate that whole blood samples should be transported refrigerated and are stable for up to 2 weeks when refrigerated.

Limitations

This test can detect variants within the coding regions, intron-exon boundaries, and the promoter region of the UGT1A1 gene. However, it may not detect deep intronic variants, regulatory region variants other than in the (TA)nTAA promoter, or variants of any size that cannot be detected by massively parallel sequencing. The assay does not focus on low-level mosaic or somatic variants, mitochondrial DNA variants, or repeat expansions. It can be impacted by technical limitations due to pseudogenes, repetitive, or homologous regions.

Test Details