S20G mutation of the amylin gene is associated with a lower body mass index in Korean type 2 diabetic patients.

Islet amyloid deposition, which is mainly composed of amylin, is a characteristic pathological finding in patients with type 2 diabetes mellitus. A missense mutation in amylin at amino acid 20 from Serine to Glycine (S20G) has been shown to be associated with type 2 diabetes. In this study, the frequency and clinical characteristics of the S20G mutation in Korean was examined with 364 unrelated type 2 diabetic and 151 non-diabetic subjects. The S20G mutation was found in seven out of 364 diabetic patients (1.92%) and in three out of 151 non-diabetic subjects (1.99%). The body mass index (BMI) of the patients with the S20G mutation was lower than those with the wild type (21.2+/-1.8 vs. 24.3+/-3.0 kg/m(2); P<0.01). The prediabetic maximum BMI was also lower in patients with the S20G mutation (22.4+/-2.3 vs. 26.4+/-3.2 kg/m(2); P<0.01). Patients with the S20G mutation had a higher HbA(1c) level than those with the wild type (9.3+/-1.4 vs. 7.7+/-1.3%; P<0.01). In summary, the frequency of the S20G mutation in the amylin gene is 1.92% in unrelated Korean type 2 diabetic patients and this mutation is associated with a lower BMI and a higher HbA(1c) level.