UGT1A1 and neutropenia: In 2008, the Ministry of Health, Labour, and Welfare of Japan likewise recommended that the package insert be revised to warn of the risk of severe irinotecan-related neutropenia in Japanese patients who are either homozygous for UGT1A1*6 or UGT1A1*28 or heterozygous for both UGT1A1*6 and UGT1A1*28.