The objectives of this investigation are designed to provide information on normal starch digestion by evaluation of individuals with known defects in early and lite digestion. 1.) to test the starch digestion of young infants with immaturity of early starch diestion. 2.) To test the starch diestion of children and adults with defects of late starch digestion documented by previous mucosal biopsies. 3.) To test the starch digestion of family members of individuals related to the subjects in objective 2 to determine starch diegestion in subjects with parital defects in late starch digestion.