EVALUATION OF AGREEMENT BETWEEN C/T-13910 POLYMORPHISM GENOTYPING RESULTS AND LACTOSE TOLERANCE TEST RESULTS: A...

Area of Science:

• Genetics
• Gastroenterology
• Clinical Diagnostics

Background:

• Lactose tolerant test (LTT) is a widely used, low-cost diagnostic method for lactose intolerance in Brazil.
• The C/T-13910 polymorphism for lactase persistence is well-studied in Caucasians, but its concordance with LTT in Brazil's mixed population is unknown.

Purpose of the Study:

• To evaluate the agreement between C/T-13910 polymorphism genotyping and LTT results in a Brazilian population.
• To assess if age or state of residence influences the agreement between these diagnostic methods.

Main Methods:

• Retrospective analysis of 404 patients from a single laboratory database across Brazilian states.
• Comparison of genetic testing for C/T-13910 polymorphism with LTT results from April 2016 to February 2019.
• Stratification of results by age groups and states (São Paulo, Rio Grande do Sul).

Main Results:

• Overall agreement between genotyping and LTT was 80.4% (325/404 patients), with moderate concordance (κ=0.42).
• Discordance was observed in 19.6% (79/404 patients), including individuals with lactase non-persistence genotype (C/C) showing normal LTT, and those with lactase persistence genotypes (C/T, T/T) showing abnormal LTT.
• Agreement was not significantly affected by age or state of residence.

Conclusions:

• The moderate agreement (κ=0.42) suggests limitations of using C/T-13910 polymorphism genotyping alone for lactose intolerance diagnosis in Brazil.
• Exploring other polymorphisms may enhance the accuracy of genetic testing for lactose intolerance.
• Further studies are recommended to investigate additional genetic markers for improved diagnostic concordance.