Alpha, alpha trehalase deficiency

**Definition:** Alpha, alpha trehalase deficiency is characterised by diarrhoea and vomiting after ingestion of trehalose, a disaccharide found mainly in mushrooms. The disease is very rare in most populations but the incidence has been estimated at least 1 in 13 in Greenland. Isolated trehalose intolerance is due to a deficiency of trehalase (TREH; 11q23.3), a brush-border membrane glycoprotein.