Hypolactasia and Lactase Persistence Historical Review and the Terminology

Abstract

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.

Teste do H2 no ar expirado na avaliação de absorção de lactose e sobrecrescimento bacteriano no intestino delgado de escolares

“…A principal razão para a grande variação da atividade enzimática é o fato da produção da enzima ser determinada geneticamente, de modo recessivo autossômico, por um gene localizado no cromossomo 2 (15) . A lactase não é uma enzima indutível, sendo Reis JC dos, Morais MB de, Fagundes-Neto U. Teste do H 2 no ar expirado na avaliação de absorção de lactose e sobrecrescimento bacteriano no intestino delgado de escolares assim, alimentar-se com lactose não impedirá declínio da sua atividade, caso isto tenha sido determinado geneticamente (17,21,22) .…”

Correlation between lactose absorption and the C/T-13910 and G/A-22018 mutations of the lactase-phlorizin hydrolase (LCT) gene in adult-type hypolactasia

“…The condition affects more than 75% of the population worldwide, with regional frequencies ranging from nearly 5% in northern Europe to more than 90% in some Asian and African countries (2).…”

Genetic tests for low- and middle-income countries: a literature review

“…It is also known as lactase deficiency due to the absence of lactase-phlorizin hydrolase (LPH). Seventy-five per cent of the world population is intolerant to lactose; however, there is significant geographic variability, with a north-south frequency gradient going from 5% in northern European populations to 80-90% in some African and Asiatic populations (Sahi, 1994). A C/T polymorphism was identified in the MCM6 (2q21-22) gene, which is 13910 bp upstream of the gene encoding LPH (LCT) and is associated with the adult-onset form of lactose intolerance, also known as lactase non-persistence.…”