Diagnosis

The diagnosis of this condition depends on the demonstration of deficient activity of sucrase and isomaltase in a biopsy specimen of the small intestine. The reason why these two enzymatic defects are present together is not known. The absence of steatorrhoea and usually of villous atrophy serves to exclude coeliac disease. If there is partial villous atrophy present then this will revert to normal after a prolonged sucrose-free diet as is provided by milk, cheese, meat, eggs, fowl, animal fat, glucose, vegetables and fish.