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 mu M 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 mu M) compared with others (9.18 +/- 3.73 mu M, p < 0.001). Conclusion: Short (GT) n alleles of the HMOX-1 gene promoter could be a genetic risk factor for hyperbilirubinemia.