The disaccharidase activities in small-intestinal surgical biopsy specimens from 97 Greenlanders were investigated. Five of the patients, or 5%, had sucrase deficiency. The diagnosis, sucrose malabsorption, was established by sucrose tolerance tests. In all parts of the world other than the arctic regions sucrase deficiency is a rare condition. The patients were divided into three separate groups in accordance with their sucrase activity. The middle group was considered to be heterozygote carriers of the sucrase-deficient gene. The number of people in the group corresponded to the theoretical number of heterozygotes in accordance with the Hardy-Weinberg equation, suggesting that sucrase deficiency is recessively inherited in a simple Mendelian fashion. Four of the five patients with sucrase deficiency had deficiency of lactase as well. The nutritional implications are discussed.

Small-intestinal surgical biopsy specimens from 97 adult Greenlanders showed an incidence of trehalase deficiency in at least 8%. Trehalose tolerance tests performed in three individuals with low trehalase activity (6 IU/g protein) showed no increase in the blood glucose concentration. Three trehalase-deficient patients had lactase deficiency too. Trehalase deficiency is not considered to have any significance from a nutritional point of view.