Lactase persistence genotyping: rapid detection of seven sequence variants in a single tube with melting curve analyses.

BACKGROUND

Lactase persistence is an inherited autosomal dominant trait that confers the ability to digest lactose after weaning. Lactose persistence is caused by single nucleotide variants in a regulatory element for the lactase gene (LCT). In Europeans, lactase persistence is associated with the nucleotide variant LCT -13910C>T. Ethnic groups from Africa and the Arabian Peninsula have other lactase persistence variants in close proximity to the -13910C>T variant. Current hybridisation probe analysis methods have been limited by the inability to detect all the known nucleotide variants. The aim of this study was to devise a method based on hybridisation probes and melting curve analysis for rapidly detecting LCT variants.

METHODS

We designed hybridisation probes for producing melting curve profiles that could identify seven LCT nucleotide variants: -13907C>G, -13910C>T, -13913T>C, -13914G>A, -13915T>G, -14009T>G, and -14010G>C. To validate the assay, we generated plasmid standards of all the alleles and mixed them to create artificial heterozygote samples.

RESULTS

All genotypes could be detected in a single tube assay. Rare genotypes were confirmed in a second assay with probes that had different complementary sequences.

CONCLUSIONS

This assay can be used for rapidly genotyping lactase persistence in multi-ethnic populations.