Intestinal disaeeharidase aetivitieswere determined in 294 jejunal biopsies obtained from 254 children with various disorders of the small bowel, and alkaline phosphatase activity was measured in 251 biopsies. In normal mucosa a broad range of enzyme activity was found corresponding with the data in the literature.
A primary disaeeharidase deficiency was observed in 5 children with congenital sueraseisomaltase deficiency and in a 12-year-old Egyptian boy with acquired laetase deficiency.
A secondary generalized depression of disaeeharidase activity and a diminution of alkaline phosphatase activity existed chiefly in patients who had severe or moderate mueosal damage, also in active coeliac disease and during gluten loading, in protracted diarrhoea of infancy, chronic malabsorption of unknown origin and agammaglobulinemia. During remissions enzyme aetivities recovered together with mucosal improvement. Low levels of enzyme activities were also seen in some eases of protracted diarrhoea of infancy and chronic malabsorption of unknown origin although only mild mueosal lesions were demonstrated.