Association of (GT)n repeats promoter polymorphism of heme oxygenase-1 gene with serum bilirubin levels in healthy Indian adults.

Aim: The present study was undertaken to investigate a length polymorphism of (GT)n repeats of the heme oxygenase-1 (HMOX-1) gene and its association with serum bilirubin levels in apparently healthy adults.

Methods: A total of 211 individuals (normal hematology and liver function test) with bilirubin levels of 1.7 to 22.2 μM were studied. The (GT)n repeats were analyzed by PCR and subsequent sizing by capillary electrophoresis on the ABI Prism 310 Genetic Analyzer.

Results: Polymorphisms of the (GT)n repeats were grouped into three classes: short (S) alleles (<20 repeats), intermediate (M) alleles (20-28 repeats), and long (L) alleles (≥ 29 repeats). The frequencies of the S, M, and L allele groups were 0.10, 0.49, and 0.41, respectively. Carriers of short alleles had significantly higher mean bilirubin levels (13.8 ± 5.10 μM) compared with others (9.18 ± 3.73 μM, p < 0.001).

Conclusion: Short (GT)n alleles of the HMOX-1 gene promoter could be a genetic risk factor for hyperbilirubinemia.