Sucrase-isomaltase (palatinase) deficiency diagnosed during adulthood

Abstract

Although the number of reported patients with primary sucrase-isomaltase deficiency (S-ID) has been stated to be from 75 to 100 (1, 2), we have identified only 12 adults (14 years or more of age) with this deficiency documented by intestinal enzyme assays (3–11). Adults with both S-ID and a primary low lactase level are not included, since they would appear to represent a different situation (12). Sucrase-isomaltase deficiency is a rare cause of maldigestion/malabsorption but is easily diagnosed with present methods. We doubt that the estimated figure of half a million individuals with S-ID in the United States (9) is accurate. However, with three (3, 6, 10) of the previously reported adults coming from our medical center, of over 500 adults who have had intestinal enzyme assays, it is probably more common in adults than present reports would indicate. We have now had the opportunity to study our fourth nonrelated adult patient with S-ID. On the basis of assays of intestinal sucrase activities and enzyme ratios, individuals have been identified as being normal or as heterozygous (reduced sucrase) or homozygous (no sucrase activity) for S-ID. Reviewing our recent patient's case and the findings in other adults, it appears that this separation is not adequate. For this reason, and to bring S-ID as it presents during adulthood into better focus, we are reporting the following case.