Disaccharidases are enzymes the break down complex sugars (like lactose) into simple sugars (like glucose) so that the intestine can absorb the nutrients. A deficiency of these enzymes in the duodenum results in a range of gastrointestinal symptoms. The common nature of such symptoms may lead to misdiagnosis of the condition as food allergy or intolerance. Dr. Powers Peterson, Medical Director, Quest Diagnostics Nichols Institute, discusses the nature of this disorder and approaches to achieve an accurate diagnosis.