Hereditary Sucrose Intolerance: Levels of Sucrase Activity in Jejunal Mucosa

Abstract

The diagnosis was confirmed by a quantitative assay of sucrase, lactase, maltase, and palatinase activities in biopsy specimens of jejunal mucosa. In all cases, there was an absence of sucrase activity, whereas lactase activity was normal. Maltase and palatinase activities were decreased and in one case, palatinase activity was absent. The significance of the enzyme pattern is discussed, in particular the association of two specific hereditary enzyme defects occurring in one patient. From a consideration of the cases diagnosed at the later ages, it appears that clinical improvement with age is accompanied neither by increased sucrose utilization nor by restoration of normal enzyme activity. The enzyme activities in the jejunal mucosa of 3 of the parents were determined, the genetics of the metabolic error are discussed, and it is concluded that the condition is inherited as an autosomal recessive.