CYP2R1-, CYP27B1- and CYP24-mRNA expression in German type 1 diabetes patients

1,25(OH)(2)D-3 and 25(OH)D-3 have been associated with type I diabetes. Diverse enzymes are involved in the synthesis of these metabolites: the 25-Vitamin-D-hydroxylase (CYP2R1), the 25-hydroxyvitamin-D3-1-alpha-hydroxylase (CYP27B1) and the 25 (OH)D-3-24-hydroxy lase (CYP24) among others. Serum levels of 25(OH)D3 and 1,25(OH)2D3 were investigated in type 1 diabetes patients (n = 173) and the mRNA expression of the CYP2R1. CYP27B1 and CYP24 genes in type I diabetes patients (it = 33) and healthy controls (n = 23). These parameters were correlated with the -1260 (C/A) polymorphism in the CYP27B1 gene. Lower expression of CYP27B1 mRNA in comparison with healthy controls (1.7165 versus 1.7815, P=0.0268) was found. Additionally, patients carrying the genotype CC possessed a reduced amount of CYP27B1 mRNA compared to healthy controls (1.6855 versus 1.8107, respectively, P=0.0220). The heterozygosity rate of the -1260 C/A polymorphism was more frequent in patients with normal levels of 1,25(OH)(2)D-3 (>= 19.9 pmol/rnl) than in whose with a level of less than 19.9 pmol/ml (46.7% versus 22.2%, P = 0.0134). No correlation with serum levels of 25(OH)D3 was found. Thus. CYP27B1 gene could play a functional role in the pathogenesis of type I diabetes through modulation of its mRNA expression and influence serum levels of 1,25(OH)(2)D-3 via the -1260 C/A polymorphism. (c) 2006 Elsevier Ltd. All rights reserved.