Introduction: Primary lactose malabsorption, adult type, is associated with the genotype CC in a lactase gene regulatory sequence (LCT-13910). In contrast, the genotype CT or TT in this position correlates with normal lactose absorption. Genotyping was implemented for routine testing of patients for primary lactose intolerance. We estimated the frequency of genotypes in a group of blood donors and compared it with the frequency among patients.
Materials and methods: In total, 478 patients admitted to a hospital or to a specialist in gastroenterology and 100 blood donors were genotyped. DNA was obtained, and the relevant DNA sequence was amplified by real-time polymerase chain reaction (PCR) and analysed by the use of melting curve analysis.
Results: Among blood donors, the allelic distribution was 8% CC, 38% CT and 54% TT, whereas 14% CC, 37% CT, 48% TT was found in the patient group.
Conclusion: Compared with the control group, the frequency of the CC genotype is almost doubled in the genotyped patients. Genotyping proved to be a convenient tool for routine clinical testing.