كليدواژه :
Primary hypolactasia , DNA sequence analysis , هايپولاكتازياي اوليه , DNA تعيين توالي
چكيده لاتين :
Introduction: Primary hypolactasia is a common disorder with an autosomal recessive pattern of inheritance. It results from a physiological decline in activity of lactase phlorizin hydrolase (LPH) in intestinal epithelium after weaning. PH is the most common enzyme deficiency in the world, with a high prevalence in Asia and Far East. Although there are a few cases of human beings in which the enzyme remains active, it usualy decreases with the age. This could eliminate the consumption of the milk and provide other limitations, such as, failure to thrive in infants and children. Recent studies of sequence analysis of LCT, the gene encoding LPH, and adjacent regions on 2g21 have revealed that a DNA variant, C/T -13910, roughly 14kb upstream from the LCT locus in intron 13 of MCM6, is strongly associated with PH. Our aim was to estimate the prevalence of primary hypolactasia by the analysis of C/T -13910.
Methods: The study population was a number of villagers and nomads setteled around Esfahan who raised cattle or earned their living by agriculture. Out of them, 44 cases were selected. DNA extraction was performed and sent to the University of Helsinki, Finland, for evaluating the C/T -13910 variant on MCM6 domain, located in 21 th chromosome.
Results: We observed C/T-13910 in 16% of the samples; in other words the prevalence of PH was 84% in this population.
Conclusion: This article is a novel study of the C/T -13910 variant in central Iran. According to the related results, and the past history of Iran, being one of the origins of agricultural pastoralism (approximately 9000 years ago), the geographical location may have an important role in establishing the persistence of C/T -13910 and the lactase enzyme in human genome. We suggest further investigations about hypolactasia in Iran that can throw light on this subject.
