Association of KCNQ1 gene polymorphism with gestational diabetes mellitus in a Chinese population

Abstract

To the Editor: Epidemiological study has confirmed that women with a history of gestational diabetes mellitus (GDM) are at increased risk of developing type 2 diabetes mellitus later in life [1]. Women with a family history of diabetes also have a significantly increased risk of GDM [2]. Some researchers consider that GDM may share some risk factors and genetic susceptibility with type 2 diabetes mellitus. KCNQ1, located at chromosome 11p15.5, encodes the pore-forming K channel alpha-subunit, which is produced in a wide variety of tissues including the pancreas. Recent evidence has revealed a strong association of KCNQ1 with susceptibility to type 2 diabetes [3, 4]. However, no studies have focused on the association between KCNQ1 gene polymorphism and GDM. Our aim in this study was to investigate the correlation between KCNQ1 variants and GDM in a Chinese population. All pregnant women were screened for GDM between 24 and 28 weeks with a 50 g glucose challenge test (GCT). Plasma glucose 1 h after intake of glucose less than 7.8 mmol/l was defined as GCT negative (GCT−), but otherwise a participant was diagnosed as GCT positive (GCT+). GCT+ women then had a 100 g oral glucose tolerance test. The glucose threshold values were: fasting, 5.3 mmol/l; 1 h, 10.0 mmol/l; 2 h, 8.6 mmol/l; and 3 h, 7.8 mmol/l. If two or more of the glucose values met or exceeded the threshold value, GDM was diagnosed; normal glucose tolerance was diagnosed when all plasma glucose values were below the threshold values. Electronic supplementary material The online version of this article (doi:10.1007/s00125-009-1500-y) contains supplementary material, which is available to authorized users. Q. Zhou :K. Zhang :W. Li : J. Hong : S. W. Qin : F. Ping : M. L. Sun :M. Nie (*) Key Laboratory of Endocrinology, Ministry of Health, Department of Endocrinology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Shuai Fuyuan 1#, Dongcheng District, Beijing 100730, People’s Republic of China e-mail: nm_pumch@yahoo.com.cn