In another study of 82 patients with a mix of functional diarrhea and constipation, a majority of patients expressed disaccharidase deficiency: 86.5% were lactase deficient, 48.7% were maltase deficient, 50% were sucrase deficient and 84.1% were gluco-amylase deficient [19]. The gene discussed is SI; the disease is hyperinsulinemic hypoglycemia, familial, 4.