Adult-type
hypolactasia results from the progressive decline of
lactase-phlorizin hydrolase activity in enterocytes after weaning.
Lactase nonpersistence may determine a primary
lactose intolerance with reduced diary product consumption, which is possibly related to an increased risk of
colon cancer. Recently, a genetic variant C/T(-13910) upstream of the
lactase-phlorizin hydrolase (LCT) gene has been strongly correlated with the
lactase persistence/nonpersistence trait in both family and case-control studies. The authors validate a denaturing high-performance liquid chromatography (dHPLC)-based assay versus conventional genotype sequencing in detecting the C/T(-13910) polymorphism of LCT and evaluate its prevalence in 2 different Italian geographical areas and in
colorectal cancer patients.
DNA samples of 157 healthy subjects and 124
colon cancer patients from Apulia and of 97 healthy subjects from Sardinia were evaluated for the C/T(-13910) polymorphism by dHPLC, sequencing, and restriction fragment length polymorphism (RFLP). Under optimized conditions, dHPLC was as sensitive as
DNA sequencing and detected a new genetic variant (T/C(-13913)) in 2 individuals that was not identified by RFLP assay. Frequency of
lactase nonpersistence genotype (C/C(-13910)) was similar in healthy subjects from 2 different Italian geographical areas and not increased in patients with
colorectal cancer. The results indicate that the dHPLC method may be used as a rapid, noninvasive, and labor-saving screening tool for genotyping C/T(-13910) polymorphism, with high success, low cost, and reproducibility.