Diarrhea and/or cholestasis are the prime symptoms of patients diagnosed with microvillus inclusion disease (MVID) (Online Mendelian Inheritance in Men #251850) and/or familial intrahepatic cholestasis and carrying bi-allelic MYO5B mutations.8, 9, 10 Moreover, MYO5B mutations have been shown to cause the mislocalization of bile acid transporters in the hepatocytes of some patients9, 10, 11 and villus atrophy and brush border abnormalities in the small intestine.8 Here, MYO5B is linked to microvillus inclusion disease.