Varnell CD, et al. - This study was established to elucidate mycophenolate mofetil-related leukopenia in children and young adults following kidney transplantation. It was reported that MMF-related leukopenia was common after transplantation. Especially in patients without lymphocyte-depleting induction, UGT2B7 seemed to influence leukopenia risk. After a transplant, IMPDH1 appeared to influence the time course of leukopenia.