OBJECTIVE: This study assessed whether the Trp(64)Arg polymorphism of the beta3-adrenergic receptor (beta3-AR), which has been associated with obesity, insulin resistance, weight gain, and earlier onset of type 2 diabetes, is more frequent in women who develop gestational diabetes mellitus (GDM) or whether it is associated with weight gain during pregnancy RESEARCH DESIGN AND METHODS: A total of 311 Greek pregnant women (180 with GDM and 131 without GDM [control]) who underwent a 100-g oral glucose tolerance test (OGTT) in the third trimester of pregnancy were genotyped for the beta3-AR Arg(64) polymorphism. Insulin levels were also determined during the OGTT. RESULTS: The frequency of Trp(64)Arg heterozygotes in this population was approximately 7% and was similar in the GDM and control groups (6.7 vs. 6.9%) as well as in the obese (BMI > or =27 kg/m2) and the nonobese (6.3 vs. 6.8%) subgroups. In the GDM group, BMI, fasting insulin resistance index, and diastolic blood pressure were significantly higher in Trp(64)Arg carriers; these differences were no longer observed when obesity was considered. In the 4 subgroups (control Trp(64)Trp and Trp(64)Arg and GDM Trp(64)Trp and Trp(64)Arg), a highly significant trend was evident of an increase in the percentage of subjects with shorter height. CONCLUSIONS: The frequency of the Arg(64) allele in Greek pregnant women is relatively rare compared with other ethnic groups and is probably not related to the development of GDM or obesity The observed tendency for shorter body height in Arg(64) carriers merits further evaluation in larger population samples.

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