HLA-DQB1 genotypes and islet cell autoantibodies against GAD65 and IA-2 in relation to development of diabetes post partum in women with gestational diabetes mellitus.

AIMS: To study HLA-DQB1 genes and islet cell autoantibodies against glutamic acid decarboxylase 65 (GADA) and insulinoma antigen-2 (IA-2A) in relation to diabetes post partum in mothers with diagnosed gestational diabetes mellitus (GDM). METHODS: During 2003-2004, women undergoing a 75g oral glucose tolerance test (OGTT) during pregnancy were invited to participate in the Mamma Study. Cut-off level defining GDM was a 2-h capillary blood glucose of 7.8mmol/L. 1-2 years after delivery a 75g OGTT was performed, GADA and IA-2A were measured and HLA-DQB1 genes analysed. Data were available for 452 mothers with previous GDM and 168 randomly selected control subjects. RESULTS: HLA-DQB1*0602 was negatively associated with GDM (p=0.033) and with development of diabetes post partum (p=0.017), whereas high risk HLA were not associated with GDM or with diabetes. The presence of GADA post partum was positively associated with diabetes post partum (p=0.0009), but not with impaired glucose tolerance. CONCLUSIONS: Mothers with GDM and HLA-DQB1*0602 were less likely to develop diabetes after pregnancy, and type 1 diabetes associated high risk HLA genes did not predict type 1 diabetes post partum. Additionally, GADA were positively associated with diabetes development.