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

Abstract

The C/T-13910 mutation is the major factor responsible for the persistence of the lactase-phlorizin hydrolase (LCT ) gene expression. Mutation G/A-22018 appears to be only in co-segregation with C/T-13910. The objective of the present study was to assess the presence of these two mutations in Brazilian individuals with and without lactose malabsorption diagnosed by the hydrogen breath test (HBT). Ten milk-tolerant and 10 milk-intolerant individuals underwent the HBT after oral ingestion of 50 g lactose (equivalent to 1 L of milk). Analyses for C/T-13910 and G/A-22018 mutations were performed using a PCR-based method. Primers were designed for this study based on the GenBank sequence. The CT/GA, CT/AA, and TT/AA genotypes (lactase persistence) were found in 10 individuals with negative HBT. The CC/GG genotype (lactase non-persistence) was found in 10 individuals, 9 of them with positive HBT results. There was a significant agreement between the presence of mutations in the LCT gene promoter and HBT results (kappa = -0.9, P < 0.001). The CT/AA genotype has not been described previously and seems to be related to lactase persistence. The present study showed a significant agreement between the occurrence of mutations G/A-22018 and C/T-13910 and lactose absorption in Brazilian subjects, suggesting that the molecular test used here could be proposed for the laboratory diagnosis of adult-type primary hypolactasia. Correspondence

Diagnosis of adult-type hypolactasia/lactase persistence: genotyping of single nucleotide polymorphism (SNP C/T-13910) is not consistent with breath test in Colombian Caribbean population

“…This is not the case for African Caribbean Colombians, because the blacks brought as slaves from Africa during the colonial period came mainly from Western Africa where the -13910*T allele is scarce (18,29) . The importance of the ethnic origin, when doing genotype-phenotype correlation studies is evident with the results recently published in Brazil by Bulhões et al (3) and Mattar et al (15) who reported perfect correlation between the SNP C/T -13910 and lactose digestion. They got this result because the subjects in their study were Brazilians of Caucasian descendence.…”

Whey Lactose as a Raw Material for Microbial Production of Biodegradable Polyesters

“…It is estimated that 75% of adults worldwide show some decrease in lactase activity (hypolactasia), resulting in lactose intolerance still during adulthood. The phenomenon "lactose intolerance" is mainly found in African, Asian, South American and South European regions (Bulhões et al, 2007). Unfortunately, this frequently occurring of lactase activity deficiency hampers a broader application of whey for nutrition of mankind.…”

Experimental study of lactose hydrolysis and separation in cstr-uf membrane reactor

“…Lactose waste increases biochemical and chemical oxygen demand (BOD and COD) which is in contrast with legal standards for wastewater (Cuartas-Uribe et al, 2009). In addition, lactose, as a disaccharide, is scarcely digestible for about 75% of adults worldwide due to lack of β-galactosidase enzyme in their body (Sieber et al, 1997;Bulhões et al, 2007). Furthermore, a high amount of lactose in dairy products like ice cream, condensed milk, etc., leads to an undesirable grainy texture.…”