[Interaction between HLA-DRB1 gene polymorphism and environmental risk factors in the development of gestational...

To explore the interactions between human leukocyte antigen (HLA) -DRB1 gene polymorphism and environmental risk factors in gestational diabetes mellitus (GDM) pathogenesis.

Pregnant women who had prenatal cares in Obstetric Department, West China Second Hospital of Sichuan University were recruited from January 1(st) to December 31(st) in 2011. A prospective cohort study was conducted in the women who had a glucose challenge test (GCT) or 75 g oral glucose tolerance test (OGTT) during 24-28 gestational weeks. A total of 104 women diagnosed with GDM were randomly included in GDM group while another 103 normal women fell into the control group. The HLA-DRB1 polymorphism was detected by Polymerase Chain Reaction - Sequence Specific Primers (PCR-SSP) method in both groups. The interactions between HLA-DRB1 polymorphism and environmental risk factors were analyzed based on the simple-case-study method.

(1) There were 712 pregnant women with complete perinatal information during January 1(st) to December 31(st) , 2011, among whom 175 (24.6%) women were diagnosed with GDM. A logistic regression analysis showed that advanced maternal age (OR = 1.081, 95%CI: 1.027- 1.138), imbalanced diet (OR = 3.329, 95%CI: 2.167-5.116), high body mass index (BMI ≥ 24.0 kg/m(2)) before pregnancy (OR = 1.095, 95%CI:1.008-1.190), HBsAg carrier status (OR = 3.173, 95%CI: 1.387-7.260) and family history of diabetes mellitus (DM) (OR = 1.798, 95%CI: 1.063-3.041) were risk factors of GDM. (2) There were 49 HLA-DRB1 genotypes and 51 HLA-DRB1 genotypes in GDM group and the control group, respectively. We further compared the genotypes that occurred in over 3 cases in either group and found that HLA-DRB1*12, 16 was only detected in 5 cases (5/103, 4.9%) in control group, and the difference was significant between the two groups (P = 0.029). HLA-DRB1*11, 16 and HLA-DRB1*09,09 were only detected in 4 cases (3.8%, 4/104) and 5 cases (4.8%, 5/104) in GDM group respectively, but without significant differences between the two groups (P > 0.05). No significant difference was found in other genotype frequencies between the two groups (P > 0.05). (3) Thirteen types of HLA-DRB1 allele were detected but no significant differences were observed in their frequencies between two groups (P > 0.05). (4) A positive interaction was detected between HLA-DRB1*07 polymorphism and advanced maternal ages (OR = 5.952, 95%CI:1.314-26.970, P = 0.022), while no interaction was found between HLA-DRB polymorphisms to other risk factors such as imbalanced diet, high body mass index (BMI ≥ 24.0 kg/m(2)), HBsAg carrier status or DM family history.

Advanced maternal age, unbalanced diet, high body mass index (BMI ≥ 24.0 kg/m(2)), HBsAg carrier status and DM family history are environmental risk factors of GDM in Chengdu. While HLA-DRB1*12, 16 genotype may be a protective genotype for GDM. There is a positive interaction between HLA-DRB1*07 polymorphism and advanced maternal age which may play a critic role in GDM development.