While maldigestion is due to reduced hydrolysis of nutrients (luminal or at the brush border level), malabsorption may be caused by (1) luminal factors (e.g. impaired hydrolysis, impaired micelle formation, limited bioavailability, bacterial overgrowth), (2) mucosal factors (impaired brush border hydrolase activity, inherited deficiencies, damaged absorbing surface, decreased absorbing surface, surgery, infiltration or infection), or (3) postabsorptive factors (e.g. obstruction of lymphatic system, deficiency in chylomicrons or beta-lipoproteins, protein-losing enteropathy) [17]. Here, MGAM is linked to Protein-losing enteropathy.