MYO5B and microvillus inclusion disease: Recently, bi-allelic MYO5B mutations have also been identified in a small number of patients with a low-GGT PFIC phenotype in the absence of congenital diarrhea [9,10,11]; MYO5B is therefore considered both the main disease gene for MVID and to represent one of the increasing number of disease genes for low-GGT type PFIC, and the delineation PFIC6 has been suggested for this disorder [15].