STX3 and microvillus inclusion disease: Mouse Rab8 conditional knockouts mimic MVID; furthermore, patients with MVID without Myosin 5b defects were found to have mutations affecting Syntaxin 3, an apical membrane SNARE (family of membrane proteins that ensure fusion between opposing membranes), suggesting that Myosin 5b, Rab8, and Syntaxin 3 may be involved in the same trafficking pathway [71,72].