The Lactase Gene C/T-13910 Polymorphism In Southern Chinese Population

Background:Lactase deficiency(LD) means lactase enzyme in the brush border of the small intestine enterocyte is absent or deficient. Adult-type hypolactasia(ATH) is common. The prevalence of ATH varies widely among ethnic background. The prevalence of ATH is high in China. In recent years there has been an increase in comsuption of milk. Symptoms of lactose intolerance are also increasing. It results in a huge direct and indirect expense.Some researches show that the T allele of a C/T transition 13910bp upstream from exon 1 of lactase gene was completely associated with lactase persistence in European populations. But there are some new single nucleotide polymorphisms in African populations. We want to assess if the -13910T allele is associated with lactase persistence in southern Chinese population.Objectives:To assess if the lactase gene-13910T allele is associated with lactase persistence in southern Chinese population. To assess if there is a new single nucleotide polymorphism which is associated with lactase persistence in southern Chinese population. Methods:Between November 2008 and Octorber 2009, 272 volunteers were randomly selected from functional gastrointestinal disorder patients in gastroenterology clinic of Sir Run Run Shaw Hospital. Every volunteer took a 20 gram lactose hydrogen breath test(HBT). DNA was extracted from EDTA-blood by using a AxyPrep blood DNA Extraction kit. Primer was designed based on GenBank sequence. The C/T-13910 and 400bp fragment were sequenced by using an automated DNA sequencer.Results:In 272 participants, there were 147 males(54.0%) and 125 females(46.0%). The mean age was 44.83±11.74 years old, the mean age of males was 43.12±11.83 years old, and that of females was 46.84±11.35 years old. The lactose HBT result was abnormal in 76.47% of all the volunteers. All the DNA samples were CC genotype. No-13910T allele was found in all these samples. No other single nucleotide polymorphism near C/T-13910 which was associated with lactase persistence in southern Chinese populations was found.Conclusion:The lactase gene C/T-13910 is not associated with lactase deficiency in southern Chinese population. The -13910T allele is not a suitable predictor of lactase persistence for southern Chinese population.