Intestinal Lactase Deficiency and Lactose Intolerance in Adults

Dahlqvist, Arne; Hammond, James M.; Crane, Robert K.; Dunphy, James V.; Littman, Armand

doi:10.1016/s0016-5085(19)34844-9

Cited by 132 publications

(25 citation statements)

References 8 publications

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“…In 1963, Auricchio et al (6) and Dahlqvist et al (27) independently described adults who had low small-intestinal lactase activity which was not, on the basis of case histories, congenital but had decreased since birth, as in animals. These and later observations disproved the previous view that intestinal lactase activity remains high throughout the human life-span.…”

Section: Hypolactasia In Manmentioning

confidence: 99%

Hypolactasia and Lactase Persistence Historical Review and the Terminology

Sahi

1994

Scandinavian Journal of Gastroenterology

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and Headquarters of the Frontier Guard, Helsinki, Finland Sahi T. Hypolactasia and lactase persistence. Historical review and the terminology. %and J Gastroenterol 19!44;29 Suppl202:1-6.Lactase (more precisely lactase-phlorizin hydrolase) is located in the brush border of the small intestinal enterocytes and is responsible for the hydrolysis of dietary lactose. The earliest studies on lactase activity in mammals were published around the turn of the century. In 1903, it was found that the dog had a very low lactase activity and therefore lactose remained unhydrolysed, causing diarrhoea. Human hypolactasia was demonstrated in 1%3, and it was soon found that it is very common, commoner than lactase persistence in most parts of the world. In 1973, adult-type hypolactasia was shown to be inherited by an autosomal recessive single gene. This article reviews the early expansion of the knowledge on lactase and hypolactasia as well as the correct terminology.(47) * Scand J Gastroenterol Downloaded from informahealthcare.com by Indiana University on 12/13/14For personal use only.

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Section: Hypolactasia In Manmentioning

confidence: 99%

Hypolactasia and Lactase Persistence Historical Review and the Terminology

Sahi

1994

Scandinavian Journal of Gastroenterology

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“…Although individual diVerences in the ability of human adults to digest milk had been remarked upon in Roman times, variation in expression of lactase was not established as a genetically determined trait until the second half of the twentieth century. Indeed before this, expression of high levels of lactase in adulthood was considered by people of European descent to be the 'normal' state of aVairs, and widespread deWciency of lactase in adults was only appreciated in the early 1960s (Auricchio et al 1963;Dahlqvist et al 1963).…”

Section: Introductionmentioning

confidence: 99%

Lactose digestion and the evolutionary genetics of lactase persistence

et al. 2008

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It has been known for some 40 years that lactase production persists into adult life in some people but not in others. However, the mechanism and evolutionary significance of this variation have proved more elusive, and continue to excite the interest of investigators from different disciplines. This genetically determined trait differs in frequency worldwide and is due to cis-acting polymorphism of regulation of lactase gene expression. A single nucleotide polymorphism located 13.9 kb upstream from the lactase gene (C-13910 > T) was proposed to be the cause, and the -13910*T allele, which is widespread in Europe was found to be located on a very extended haplotype of 500 kb or more. The long region of haplotype conservation reflects a recent origin, and this, together with high frequencies, is evidence of positive selection, but also means that -13910*T might be an associated marker, rather than being causal of lactase persistence itself. Doubt about function was increased when it was shown that the original SNP did not account for lactase persistence in most African populations. However, the recent discovery that there are several other SNPs associated with lactase persistence in close proximity (within 100 bp), and that they all reside in a piece of sequence that has enhancer function in vitro, does suggest that they may each be functional, and their occurrence on different haplotype backgrounds shows that several independent mutations led to lactase persistence. Here we provide access to a database of worldwide distributions of lactase persistence and of the C-13910*T allele, as well as reviewing lactase molecular and population genetics and the role of selection in determining present day distributions of the lactase persistence phenotype.

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“…Lactose malabsorption is a frequent cause of chronic or intermittent diarrhoea and other abdominal complaints (Dahlqvist, Hammond, Crane, Dunphy, and Littman, 1963;Auricchio, Rubino, Landolt, Semenza, and Prader, 1963). Therefore the beneficial effect of a milk-free diet in ulcerative colitis might be ascribed to associated lactose malabsorption.…”

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confidence: 99%