Variants of organic anion transporter polypeptide 2 gene are not risk factors associated with severe neonatal hyperbilirubinemia.

ABSTRACT

OBJECTIVES: This study aimed to determine the prevalence of four variants of organic anion transporter polypeptide 2 (OATP2) gene, and their association with severe hyperbilirubinemia. DESIGN: Observational study. SETTING: A tertiary university unit. PATIENTS Term infants of Chinese descent. METHODS: 175 infants, consisting of 65 admitted for treatment of severe hyperbilirubinemia (with serum bilirubin levels > 250 mmol/L at age 1-2 days or > 300 micromol/L at age > or = 3 days) and 110 randomly selected inborn infants without severe hyperbilirubinemia during their first month of life, were recruited. Their blood samples were subjected to sequencing analysis of exon 4 and exon 5 of OATP2 gene for detection of c.388A > G, c.521T > C, c.571T > C and c.597C > T variants. RESULTS: The c.388A > G variant was the most common, and the c.521 T > C was least common, being present in 90.9% and 26.9% of the infants, respectively. Forward logistic regression analysis showed that the only significant risk factors associated with severe hyperbilirubinemia among these Chinese infants were exclusive breast feeding (adjusted odds ratio (OR) = 12.5, 95% C.I. 2.9, 53.4; p = 0.001), infants with homozygous 211 variant of the UDPG 1A1 gene (adjusted OR = 37.7, 95% C.I. 4.4, 324.1; p = 0.001), and G6PD enzyme level < 8.5 IU/g Hb (adjusted OR = 7.3, 95% C.I. 3.1, 17.5; p < 0.00001). Gestational age, G6PD mutation status, actual G6PD enzyme level, and the 4 variants of the OATP2 gene mutation were not significant risk factors. CONCLUSION: Variants of OATP2 gene were not significant risk factors associated with severe hyperbilirubinemia in Malaysian Chinese infants.