TBC1D4 and type 2 diabetes mellitus: Importantly, a common loss-of-function mutation in TBC1D4 (p.Arg684Ter) has been recently discovered in the Greenlandic Inuit population where the homozygous carriers of the mutant allele show severely impaired postprandial disposal of glucose and a more than 10-fold increased risk of developing type 2 diabetes [159].