In humans MPI deficiency leads to a clinically identified disorder (CDG-1b= MPI-CDG); it is extremely rare (<1:1,000,000) and characterized by protein-losing enteropathy (PLE), chronic diarrhea, cirrhosis, cyclic vomiting, anemia, and hyperinsulinemic hypoglycemia. This evidence concerns the gene MPI and congenital disorder of glycosylation.