Correlation of intestinal disaccharidase activities with the C/T-13910 variant and age

AIM: To correlate the C/T-13910 variant, associated with lactase persistence/non-persistence (adult-type hypolactasia) trait, with intestinal disaccharidase activities in different age groups of the adult population. METHODS: Intestinal biopsies were obtained from 222 adults aged 18 to 83 years undergoing upper gastrointestinal endoscopy because of unspecified abdominal complaints. The biopsies were assayed for lactase, sucrase and maltase activities and genotyped for the C/T-13910 variant using PCR-minisequencing. RESULTS: There was a significant correlation between lactase activity and the C/T-13910 variant (P < 0.00001). The mean level of lactase activity among subjects with C/C-13910 genotype was 6.86 0.35 U/g, with C/T-13910 genotype 37.8 +/- 1.4 U/g, and with T/T-13910 genotype 57.6 +/- 2.4 U/g protein, showing a trimodal distribution of this enzyme activity. Significant differences were also observed in maltase activities among individuals with different C/T-13910 genotypes (P = 0.005). In contrast, in sucrase activity, no significant differences emerged between the C/T-13910 genotypes (P = 0.14). There were no statistical differences in lactase (P = 0.84), sucrase (P = 0.18), or maltase activity (P = 0.24) among different age groups. In the majority (> 84%) of the patients with the C/C-13910 genotype associated with lactase non-persistence, the lactase activity was less than 10 U/g protein. CONCLUSION: Our study demonstrates a statistically significant correlation between the C/T-13910 genotype and lactase activity and this correlation is not affected by age in adults but the cut-off value of 20 U/g protein used for the diagnosis of lactase non-persistence might be too high. (c) 2007 WJG. All rights reserved.