Investigation into the cause of breast milk jaundice and the mechanism of UG1A1

• Project/Area Number: 24791058
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Pediatrics
• Research Institution: Shiga University of Medical Science
• Principal Investigator: MATSUI Katsuyuki 滋賀医科大学, 医学部, 助教 (60595924)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Project Status: Completed (Fiscal Year 2014)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2014: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2013: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2012: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
• Keywords: 母乳性黄疸 / UGT1A1 / UGT１A1 / 転写活性

Outline of Final Research Achievements

At an obligatory neonatal health check at 1 month of age, a random population of 50 Japanese newborn had a blood test and a genetic test of UG1A1. Though higher rate of breast milk in total milk intake was related to higher concentration of serum total bilirubin (TB), rate of breast milk excluding exclusive breast-fed (EBF) infants was not related to concentration of TB. Mean concentration of TB in EBF infants was higher than that in other infants (mean ± SD; 8.71 ± 3.77 mg/dL vs. 4.31 ± 2.58 mg/dL, p<0.001). Exclusive breast-feeding was considered as an important factor of hyperbilirubinemia.
Analyses of blood test and a genetic test of UG1A1 revealed that hetero p.G71R UGT1A1 raised TB 2.0-fold higher than wild type. The impact was as same as that of EBF. Additionally, biliary function was positively correlated to BT. Biliary function had a comparable impact for TB as EBF infants and hetero p.G71R.