Isolated Lactase Deficiency

Abstract

Several studies concerning isolated lactase deficiency have appeared recently.^1-9Agreement has not been reached, however, concerning the interpretation of human intestinal disaccharidase activity¹⁰and the lactose tolerance test.^11,12Previous studies from our laboratory reported early experience with oral tolerance tests using different amounts of lactose¹³and described seven individuals with isolated lactase deficiency.^14,15Through a cooperative study involving three medical centers, we have now accumulated data on 47 individuals with this defect. The current report compares the findings in these persons with those in a group of subjects with normal lactase activity and presents our concept of the significance of an isolated lactase deficiency based on these results. <h3>Material and Methods</h3> The studies were done on 170 individuals. There were 109 males, 61 females, 145 whites, 22 Negroes, and three American Indians. The patients ranged in age from 3 to 80 years with only three