Primary hypolactasia diagnosis: Comparison between the gaxilose test, shortened lactose tolerance test, and clinical parameters corresponding to the C/T-13910 polymorphism

Jiménez, José Luís; Fernández-Suárez, Antonio; Colmenero, Aurora Úrsula Muñoz; Cantillo, Daniel Fatela; Pelayo, I.

doi:10.1016/j.clnu.2016.01.006

Cited by 13 publications

(17 citation statements)

References 29 publications

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“…Our population had a low prevalence of the LP allele (34.1%), slightly lower than that reported in other Spanish series [ 10 , 11 , 12 ]. Even though we observed a strong correlation between genotype and lactose malabsorption in children ( p < 2.2 × 10 −16 ; Cramér’s V, 0.54), in line with the findings of studies in adult populations [ 20 , 21 , 22 , 23 , 24 ], we believe that, from a practical perspective, the most important correlation to evaluate is the extent to which genotype is associated with the presence of GI symptoms.…”

Section: Discussioncontrasting

confidence: 71%

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Clinical Utility of LCT Genotyping in Children with Suspected Functional Gastrointestinal Disorder

2020

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Genetic testing is a good predictor of lactase persistence (LP) in specific populations but its clinical utility in children is less clear. We assessed the role of lactose malabsorption in functional gastrointestinal disorders (FGID) in children and the correlation between the lactase non-persistence (LNP) genotype and phenotype, based on exhaled hydrogen and gastrointestinal symptoms, during a hydrogen breath test (HBT). We also evaluate dairy consumption in this sample. We conducted a 10-year cross-sectional study in a cohort of 493 children with suspected FGID defined by Roma IV criteria. Distribution of the C/T-13910 genotype was as follows: CC, 46.0%; TT, 14.4% (LP allele frequency, 34.1%). The phenotype frequencies of lactose malabsorption and intolerance were 36.3% and 41.5%, respectively. We observed a strong correlation between genotype and both lactose malabsorption (Cramér’s V, 0.28) and intolerance (Cramér’s V, 0.54). The frequency of the LNP genotype (p = 0.002) and of malabsorption and intolerance increased with age (p = 0.001 and 0.002, respectively). In 61% of children, evaluated dairy consumption was less than recommended. No association was observed between dairy intake and diagnosis. In conclusion, we found a significant correlation between genotype and phenotype, greater in older children, suggesting that the clinical value of genetic testing increases with age.

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Section: Discussioncontrasting

confidence: 71%

“…The distribution of these different lactase phenotypes in human populations is highly variable [ 8 ]. Spanish series have reported frequencies of the LCT persistence allele ranging from 36.8% to 66% [ 9 , 10 , 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

Clinical Utility of LCT Genotyping in Children with Suspected Functional Gastrointestinal Disorder

2020

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“…In a manufacturer-sponsored trial, the diagnostic accuracy of gaxilose tests (0.93) was higher than HBT (0.85) or lactose tolerance tests (0.79) in comparison to duodenal biopsies 71. However, this was not confirmed in an independent study when the genetic test (LCT-13’910:C/T) was used as reference 72…”

Section: Testing For Lactose Malabsorption and Intolerancementioning

confidence: 92%

Update on lactose malabsorption and intolerance: pathogenesis, diagnosis and clinical management

Misselwitz

Butter

Verbeke

et al. 2019

Gut

247

256

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Lactose is the main source of calories in milk, an essential nutriedigestion, patients with visceral hypersensitivity nt in infancy and a key part of the diet in populations that maintain the ability to digest this disaccharide in adulthood. Lactase deficiency (LD) is the failure to express the enzyme that hydrolyses lactose into galactose and glucose in the small intestine. The genetic mechanism of lactase persistence in adult Caucasians is mediated by a single C→T nucleotide polymorphism at the LCTbo −13’910 locus on chromosome-2. Lactose malabsorption (LM) refers to any cause of failure to digest and/or absorb lactose in the small intestine. This includes primary genetic and also secondary LD due to infection or other conditions that affect the mucosal integrity of the small bowel. Lactose intolerance (LI) is defined as the onset of abdominal symptoms such as abdominal pain, bloating and diarrhoea after lactose ingestion by an individual with LM. The likelihood of LI depends on the lactose dose, lactase expression and the intestinal microbiome. Independent of lactose digestion, patients with visceral hypersensitivity associated with anxiety or the Irritable Bowel Syndrome (IBS) are at increased risk of the condition. Diagnostic investigations available to diagnose LM and LI include genetic, endoscopic and physiological tests. The association between self-reported LI, objective findings and clinical outcome of dietary intervention is variable. Treatment of LI can include low-lactose diet, lactase supplementation and, potentially, colonic adaptation by prebiotics. The clinical outcome of these treatments is modest, because lactose is just one of a number of poorly absorbed carbohydrates which can cause symptoms by similar mechanisms.

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“…However, this is an invasive technique for a relatively minor condition. Other more readily measurable, cost-effective and less invasive methods are therefore preferred [11,12].…”

Section: Introductionmentioning

confidence: 99%

“…Other indirect methods used include measurement of breath hydrogen (H 2 ; which indicates fermentation of undigested lactose from colonic bacteria [21,22]), blood glucose and urinary galactose, indicating hydrolysis of lactose. An incremental rise in breath H 2 above 20 ppm [23][24][25] and reduction of plasma glucose below 1.11 mmol/L following lactose challenge [12,26] indicate LM or LNP. Urinary galactose is frequently reported using a variety of testing procedures and reporting methods [27][28][29][30] limiting direct comparisons within the literature.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of breath, plasma, and urinary markers of lactose malabsorption to diagnose lactase non-persistence following lactose or milk ingestion

et al. 2020

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Background: Adult lactase non-persistence (LNP) is due to low lactase expression, resulting in lactose malabsorption (LM). LNP is a genetic trait, but is typically determined by LM markers including breath H 2 , blood glucose, and urinary galactose after a lactose tolerance test. Known validity of these markers using milk is limited, despite being common practice. Compositional variation, such as β-casein variants, in milk may impact diagnostic efficacy. This study aimed to evaluate the diagnostic accuracy to detect LNP using these commonly measured LM markers after both lactose and milk challenges.Methods: Fourty healthy young women were challenged with 50 g lactose then randomized for separate crossover visits to ingest 750 mL milk (37.5 g lactose) as conventional (both A1 and A2 β-casein) and A1 β-casein-free (a2 Milk™) milk. Blood, breath and urine were collected prior to and up to 3 h following each challenge. The presence of C/T 13910 and G/A 22018 polymorphisms, determined by restriction fragment length polymorphism, was used as the diagnostic reference for LNP.Results: Genetic testing identified 14 out of 40 subjects as having LNP (C/C 13910 and G/G 22018 ). All three LM markers (breath H 2 , plasma glucose and urinary galactose/creatinine) discriminated between lactase persistence (LP) and LNP following lactose challenge with an area under the receiver operating characteristic (ROC) curve (AUC) of 1.00, 0.75 and 0.73, respectively. Plasma glucose and urinary galactose/creatinine were unreliable (AUC < 0.70) after milk ingestion. The specificity of breath H 2 remained high (100%) when milk was used, but sensitivity was reduced with conventional (92.9%) and a2 Milk™ (78.6%) compared to lactose (sensitivities adjusted for lactose content). The breath H 2 optimal cut-off value was lower with a2 Milk™ (13 ppm) than conventional milk (21 ppm). Using existing literature cut-off values the sensitivity and specificity of breath H 2 was greater than plasma glucose to detect LNP following lactose challenge whereas values obtained for urinary galactose/creatinine were lower than the existing literature cut-offs.

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Primary hypolactasia diagnosis: Comparison between the gaxilose test, shortened lactose tolerance test, and clinical parameters corresponding to the C/T-13910 polymorphism

Cited by 13 publications

References 29 publications

Clinical Utility of LCT Genotyping in Children with Suspected Functional Gastrointestinal Disorder

Clinical Utility of LCT Genotyping in Children with Suspected Functional Gastrointestinal Disorder

Update on lactose malabsorption and intolerance: pathogenesis, diagnosis and clinical management

Evaluation of breath, plasma, and urinary markers of lactose malabsorption to diagnose lactase non-persistence following lactose or milk ingestion

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