Genetics of Lactose Intolerance: An Updated Review and Online Interactive World Maps of Phenotype and Genotype Frequencies

Abstract

In humans the ability to digest milk lactose is conferred by a β-galactosidase enzyme called lactase-phlorizin hydrolase (LPH). While in some humans (approximately two-thirds of humankind) the levels of this enzyme decline drastically after the weaning phase (a trait known as lactase non-persistence (LNP)), some other individuals are capable of maintaining high levels of LPH lifelong (lactase persistence (LP)), thus being able to digest milk during adulthood. Both lactase phenotypes in humans present a complex genetic basis and have been widely investigated during the last decades. The distribution of lactase phenotypes and their associated single nucleotide polymorphisms (SNPs) across human populations has also been extensively studied, though not recently reviewed. All available information has always been presented in the form of static world maps or large dimension tables, so that it would benefit from the newly available visualization tools, such as interactive world maps. Taking all this into consideration, the aims of the present review were: (1) to gather and summarize all available information on LNP and LP genetic mechanisms and evolutionary adaptation theories, and (2) to create online interactive world maps, including all LP phenotype and genotype frequency data reported to date. As a result, we have created two online interactive resources, which constitute an upgrade over previously published static world maps, and allow users a personalized data exploration, while at the same time accessing complete reports by population or ethnicity.

Ileal Lactase Expression Associates with Lactase Persistence Genotypes

“…Depending on the ethnicity, up to 70% of adults suffer from lactose intolerance as a result of a progressive decrease in intestinal lactase activity [ 11 ]. Genotyping rs4988235 (and the closely correlated rs182549) is considered to enable diagnosis of lactose intolerance in symptomatic patients older than six years [ 24 ] and may be considered to have accuracy increasing with age [ 3 ].…”

“…The autosomal dominant inheritance pattern has enabled dairy intake in various populations around the world, probably reflecting adaptation to evolutionary pressures of changing lifestyles, including animal domestication [ 7 ]. The highest frequency of LP characterizes descendants of northern Europeans and some ethnic groups in Africa, which harbor distinct persistence polymorphisms [ 7 , 8 , 9 , 10 , 11 ]. LP is rarely found in South-East Asia and generally, the frequency of variants enabling lactose digestion in the adulthood falls from northwest to southeastern regions of Europe, Asia, and Africa [ 11 ].…”

<p>Korelasi usia kronologis dan pola tumbuh kembang gigi molar ketiga mandibula perempuan ditinjau dari radiograf panoramik</p><p>The correlation of chronological age and growth pattern of female mandibular third molar observed from panoramic radiographs </p>

“…Penelitian Rankinen dan Bouchard mengenai genetik dari asupan makanan dan kebiasaan makan menyebutkan bahwa pengamatan dari studi keluarga dan kembar mendukung gagasan bahwa faktor genetik berkontribusi terhadap variasi manusia dalam asupan makanan dan kebiasaan makan. 20 Pengamatan dari gangguan gen tunggal mendorong perubahan minor dalam urutan DNA pada gen kunci yang mungkin memiliki dampak pada asupan makanan. Hal ini berarti DNA memiliki pengaruh pada asupan makanan dan kebiasaan makan yang juga berpengaruh terhadap tumbuh kembang gigi.…”

A New Food Composition Database of Lactose-Free Products Commercialized in Spain: Differences in Nutritional Composition as Compared to Traditional Products

“…This incidence increases up to 60% in the Mediterranean countries [ 4 ]. A recent review by Anguita-Ruiz et al [ 5 ] gathers all lactose persistence phenotype and genotype frequency data reported worldwide. According to this source, only one-third of humans can digest milk and other lactose-rich dairy products during adulthood.…”

“…According to this source, only one-third of humans can digest milk and other lactose-rich dairy products during adulthood. In Spain, frequencies of lactase persistence range from 47% to 91%, depending on the populations studied [ 5 ].…”