Comparison of Quick Lactose Intolerance Test in duodenal biopsies of dyspeptic patients with single nucleotide polymorphism LCT-13910C>T associated with primary hypolactasia/lactase-persistence

Abstract

PURPOSE: To analyze the usefulness of Quick Lactose Intolerance Test in relation to the genetic test based on LCT-13910C>T genotypes, previously validated for clinical practice, for primary hypolactasia/lactase-persistence diagnosis. METHODS: Thirty-two dyspeptic patients that underwent upper gastrointestinal endoscopy entered the study. Two postbulbar duodenal biopsies were taken for the Quick test, and gastric antral biopsy for DNA extraction and LCT-13910C>T polymorphism analysis. DNA was also extracted from biopsies after being used in the Quick Test that was kept frozen until extraction. RESULTS: Nine patients with lactase-persistence genotype (LCT-13910CT or LCT-13910TT) had normolactasia, eleven patients with hypolactasia genotype (LCT-13910CC) had severe hypolactasia, and among twelve with mild hypolactasia, except for one that had LCT-13910CT genotype, all the others had hypolactasia genotype. The agreement between genetic test and quick test was high (p<0.0001; Kappa Index 0.92). Most of the patients that reported symptoms with lactose-containing food ingestion had severe hypolactasia (p<0.05). Amplification with good quality PCR product was also obtained with DNA extracted from biopsies previously used in the Quick Test; thus, for the future studies antral gastric biopsies for genetic test would be unnecessary. CONCLUSION: Quick test is highly sensitive and specific for hypolactasia diagnosis and indicated those patients with symptoms of lactose intolerance.

Lactose Intolerance—Old and New Knowledge on Pathophysiological Mechanisms, Diagnosis, and Treatment

“…Furthermore, the execution of the incubation of the samples must be carried out quickly and this requires the presence of a laboratory technician in the endoscopy room. This test could be used in the case of patients for whom there are other indications for an endoscopic examination [8,30].…”

Клінічні Форми Лактазної Недостатності В Дітей

“…Процес синтезу й активації лактази досить складний і складається з декількох етапів, порушення на будь-якому з них може призвести до розвитку патології [3]. Цей фермент знаходиться на апікальній поверхні щіткової облямівки ентероциту.…”

Classificação da intolerância à lactose: uma visão geral sobre causas e tratamentos

“…Nesse contexto, a aceitação do leite e de seus derivados por pessoas que apresentam essa deficiência enzimática pode variar de acordo com o grau de sua intolerância [5][6][7]. A intolerância à lactose pode ser classificada em deficiência primária, secundária ou congênita, como se verá adiante [8,9]. O entendimento da evolução dos casos de intolerância à lactose pode ser de grande relevância na perspectiva clínica do paciente portador dessa alteração, pois poderá auxiliar no desenvolvimento de novas pesquisas e tratamentos.…”

“…No método de avaliação de nitrogênio expirado, essa alteração da enzima poderá ser diagnosticada. Esse teste respiratório é um exame que utiliza a medida do hidrogênio respiratório para diagnosticar a intolerância à lactose, sendo o padrão-ouro para o diagnóstico [8,9]. http://dx.doi.org/10.24220/2318-0897v26n3a3812…”