Intracellular Trafficking Defects in Congenital Intestinal and Hepatic Diseases

ABSTRACT Enterocytes and liver cells fulfill important metabolic and barrier functions and are responsible for crucial vectorial secretive and absorptive processes. To date, genetic diseases affecting metabolic enzymes or transmembrane transporters in the intestine and the liver are better comprehended than mutations affecting intracellular trafficking. In this review, we explore the emerging knowledge on intracellular trafficking defects and their clinical manifestations in both the intestine and the liver. We provide a detailed overview including more investigated diseases such as the canonical, variant and associated forms of microvillus inclusion disease, as well as recently described pathologies, highlighting the complexity and disease relevance of several trafficking pathways. We give examples of how intracellular trafficking hubs, such as the apical recycling endosome system, the trans‐Golgi network, lysosomes, or the Golgi‐to‐endoplasmic reticulum transport are involved in the pathomechanism and lead to disease. Ultimately, understanding these processes could spark novel therapeutic approaches, which would greatly improve the quality of life of the affected patients. In this study, we investigated errors of polarized protein trafficking leading to congenital intestinal or hepatic illnesses. We provide an up‐to‐date overview of the affected genes and related trafficking machineries, disease‐relevant pathomechanisms, as well as insights into the novelties of the field.