Genetic variation in the G-50T polymorphism of the cytochrome P450 epoxygenase CYP2J2 gene and the risk of younger onset type 2 diabetes among Chinese population: potential interaction with body mass index and family history.
BACKGROUND
Cytochrome P450 (CYP) 2J2 is a regulatory enzyme in the biosynthesis of biologically active CIS-epoxyeicosatrienoic acids (EETs). EETs have been suggested to modulate PPAR-gamma and PPAR-alpha transcription activity and play a role in stimulus-secretion coupling in pancreatic beta cells. Genetic abnormalities in the expression of CYP2J enzymes may play a role in the pathogenesis of type 2 diabetes mellitus (T2DM). Our objective was to investigate CYP2J2 G-50T polymorphism (rs890293) in association with insulin resistance markers and T2DM in a Chinese population.


METHODS
A total of 1 747 Chinese T2DM patients and 994 non-diabetic subjects were studied. The CYP2J2 G-50T polymorphism was determined by a restriction fragment-length polymorphism polymerase chain reaction.


RESULTS
Neither the CYP2J2 genotype distribution nor allele frequency differed between the control subjects and the T2DM patients. However, among diabetics, subjects with a younger age at diagnosis (AAD; <40 years) had significantly higher T variant frequency than those with an AAD>/=40 years. When diabetic patients were stratified by their AAD in 10-year intervals, the trend was significantly linear among age grades. A significant interaction between the CYP2J2 T variant and younger onset diabetic subjects with positive family diabetes history, and BMI>/=27 kg/m (2) were observed to have the highest risk of diabetes and younger onset diabetics with the T variant had higher homeostasis model assessment estimate of insulin resistance (HOMA-IR) and HOMA-beta values than their GG genotype counterparts. Plasma concentrations of stable EET metabolites were significantly lower in individuals with the G-50T SNP in younger onset diabetics.


CONCLUSIONS
These data suggest that age of onset, family history, and obesity may modify the association between the CYP2J2 G-50T polymorphism and T2DM risk. CYP2J2 G-50T polymorphism may contribute to the pathogenesis of T2DM, partially by effects on insulin resistance, in patients with younger onset T2DM.
Wang
C-P
CP
Division of Cardiology, Department of Internal Medicine, E-Da Hospital, I-Shou University, Kaohsiung, Taiwan.
Hung
W-C
WC
Yu
T-H
TH
Chiu
C-A
CA
Lu
L-F
LF
Chung
F-M
FM
Hung
C-H
CH
Shin
S-J
SJ
Chen
H-J
HJ
Lee
Y-J
YJ
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D044466:Asian People / Q000235:genetics; D015992:Body Mass Index; D002681:China; D000090762:Cytochrome P-450 CYP2J2; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D003924:Diabetes Mellitus, Type 2 / Q000201:enzymology / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006801:Humans; D007333:Insulin Resistance / Q000235:genetics; D008487:Medical History Taking; D009765:Obesity / Q000235:genetics; D010105:Oxygenases / Q000235:genetics; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D020641:Polymorphism, Single Nucleotide; D018570:Risk Assessment
C000717350:CYP2J2 protein, human; D003577:Cytochrome P-450 Enzyme System; D010105:Oxygenases; D000090762:Cytochrome P-450 CYP2J2