Maltase-glucoamylaseis a brush borderhydrolasethat serves as an alternate pathway for starch digestion that complements sucrase-isomaltase activity. Congenital maltase-glucoamylase deficiency is rare, with only several cases described in the literature. Genetically, maltase-glucoamylase shares approximately 59% of its sequence with sucrase-isomaltase, and the enzyme has two catalytic sites that are identical to those of sucrase-isomaltase.Symptomsare similar to those seen in CSID. Diagnosis requires the demonstration of reducedglucoamylaseactivity in the setting of normal small bowel histology and normal pancreaticamylaseactivity.Maltase-glucoamylaseis a brush borderhydrolasethat serves as an alternate pathway for starch digestion that complements sucrase-isomaltase activity. Congenital maltase-glucoamylase deficiency is rare, with only several cases described in the literature. Genetically, maltase-glucoamylase shares approximately 59% of its sequence with sucrase-isomaltase, and the enzyme has two catalytic sites that are identical to those of sucrase-isomaltase.Symptomsare similar to those seen in CSID. Diagnosis requires the demonstration of reducedglucoamylaseactivity in the setting of normal small bowel histology and normal pancreaticamylaseactivity.