title: Variability in the rate of 6-mercaptopurine methylation in the erythrocytes, liver and kidney in an Italian population.
abstract: OBJECTIVE
  The polymorphism of erythrocyte thiopurine methyltransferase (TPMT) is genetically regulated as an autosomal codominant trait, and so should be congenital.
  
  
  RESULTS
  We tested this hypothesis by measuring TPMT activity in erythrocyte preparations from adults and newborns and observed polymorphic distribution of TPMT activity in the adult and newborn erythrocytes. The activity of TPMT was higher in red cells from the newborns than adults. The frequency distribution of TPMT activity was also investigated in the liver and kidney. In the kidney, TPMT activity fell into two subgroups, whereas in the liver the distribution pattern was more complex. The activity of TPMT in erythrocytes and liver from the same subject was correlated, but the values of only half the cases fell within the 95% confidence limits, suggesting that the control of hepatic and/or erythrocyte TPMT is multifactorial.
authors.affiliation: Department of Biomedicine, Medical School, Pisa, Italy.
authors.forename: M A
authors.initials: MA
authors.lastname: Ferroni
authors.forename: G
authors.initials: G
authors.lastname: Marchi
authors.forename: E
authors.initials: E
authors.lastname: Sansone
authors.forename: P
authors.initials: P
authors.lastname: Romeo
authors.forename: P C
authors.initials: PC
authors.lastname: Giulianotti
authors.forename: A
authors.initials: A
authors.lastname: Pietrabissa
authors.forename: F
authors.initials: F
authors.lastname: Mosca
authors.forename: G M
authors.initials: GM
authors.lastname: Pacifici
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic / Q000097:blood* / Q000378:metabolism; D004912:Erythrocytes / Q000201:enzymology*; D005260:Female; D005312:Fetal Blood / Q000201:enzymology; D006801:Humans; D007231:Infant, Newborn; D007558:Italy; D007668:Kidney / Q000201:enzymology*; D008099:Liver / Q000201:enzymology*; D008297:Male; D015122:Mercaptopurine / Q000378:metabolism*; D008745:Methylation; D008780:Methyltransferases / Q000097:blood* / Q000235:genetics; D008875:Middle Aged; D011110:Polymorphism, Genetic
chemical_list: D000964:Antimetabolites, Antineoplastic; D015122:Mercaptopurine; D008780:Methyltransferases; C022745:thiopurine methyltransferase