Maltotrioosi

Maltotrioosi is a rare inherited metabolic disorder characterized by impaired breakdown of maltotriose, a trisaccharide formed when starch is partially digested. The disorder is thought to result from deficiency or dysfunction of intestinal brush-border α-glucosidases that normally hydrolyze maltotriose into glucose. As a consequence, maltotriose accumulates in the gut, causing malabsorption and related gastrointestinal symptoms.

Clinical presentation varies, but typically appears in infancy or early childhood and includes chronic diarrhea, abdominal discomfort, bloating, poor weight gain or growth, and sometimes episodic hypoglycemia after carbohydrate-rich meals. Some individuals may have intermittent vomiting or irritability. The severity is highly variable.

Diagnosis relies on clinical suspicion supported by specialized testing. Laboratory assessment may measure maltotriose or related metabolites in urine or blood, and enzyme assays of intestinal brush-border activity can be informative. Genetic testing can identify mutations in genes encoding enzymes involved in maltotriose digestion and transport. Differential diagnosis includes other carbohydrate malabsorption disorders such as lactose intolerance and sucrase-isomaltase deficiency.

Management focuses on dietary modification to reduce maltotriose exposure and optimize energy intake. This may involve restricting foods rich in starch-derived oligosaccharides and using alternative carbohydrate sources, along with nutritional support as needed. The prognosis depends on the underlying genetic defect and the degree of enzyme dysfunction. Research into precise molecular mechanisms and treatment strategies is ongoing.

See also: carbohydrate malabsorption disorders; inborn errors of carbohydrate metabolism.