Prevalence of adult-type hypolactasia as diagnosed with genetic and lactose hydrogen breath tests in Hungarians.

The prevalence of adult-type hypolactasia varies ethnically and geographically among populations. A C/T(-13910) single nucleotide polymorphism (SNP), upstream of the lactase gene, is known to be associated with lactase non-persistence. The aim of this study was to determine the prevalence of lactase-persistent and non-persistent genotypes in the Hungarian population, the age at onset and the applicability of the lactose H2 breath test in comparison with genetic screening. The prevalence of the C/C(-13910) genotype among adults was 37%. Hypolactasia starts to appear at around 5 years of age. Over the age of 12 years, almost all of those with a C/C(-13910) genotype have lactase non-persistence. The C/C(-13910) genotype was closely associated with a positive lactose H2 breath test in symptomatic children, whereas the lactase-persistent genotypes correlated better with a negative H2 test in a control group. In conclusion, supplementary non-invasive breath and genotyping tests furnish a perfect clinical diagnosis.