A case of hepatocyte nuclear factor‐1β (TCF2) maturity onset diabetes of the young misdiagnosed as type 1 diabetes and treated unnecessarily with insulin (一例肝细胞核因子‐1b (TCF2)突变的青年人中的成年发病型糖尿病（MODY）被误诊为1型糖尿病并且被不必要地使用胰岛素治疗)