Several putative biomarkers of EED were measured within this study: citrulline reflecting enterocyte mass; alpha-1-antitrypsin, reflecting protein-losing enteropathy; calprotectin, reflecting intestinal inflammation; immunoglobulin levels in the duodenum, the feces and the blood as well as cytokine levels in the blood as general markers of inflammation; the lactitol–mannitol ratio, reflecting intestinal permeability; endocab levels, reflecting translocation of Gram-negative bacteria and Igf1 (insulin-like growth factor) and branched-chain amino acids as general read-outs for undernutrition. The gene discussed is SERPINA1; the disease is Protein-losing enteropathy.