C-terminal Motifs of HIV-1 gp41 as Possible Determinants of Viral Pathogenesis / Motivos C-terminales de gp41 del VIH-1 como posibles determinantes de la patogénesis viral / Motivos C-terminais do HIV-1 gp41 como Possíveis Determinantes da Patogénese Viral

Abstract: human immunodeficiency virus type 1 (HIV-1) is the etiological agent of acquired immunodeficiency syndrome (AIDS), a pandemic with high economic and social costs. The envelope glycoprotein (ENV) of the virus mediates the infectious process by binding to and entering the host cell, one of the main target components of studies since its discovery. Its endodomain or C-terminal tail (CTT) participates in late replicative cycle processes, such as intracellular trafficking, activation, and cell death, which occurs because it interacts with multiple cellular factors through motifs or signal sequences present throughout its structure. Although these interactions have not been fully understood at specific levels, studies over more than three decades leave no doubtthatthis domain plays a fundamental role in the biology of the virus and probably the development of the disease. This review describes the studies carried out to date that demonstrate the importance of the CTT, focusing on the motifs responsible for its interactions and its possible roles in the pathogenicity of the infection.

Resumen: el virus de la inmunodeficiencia humana tipo 1 (VIH-1) es el agente etiológico del síndrome de inmunodeficiencia adguirida (SIDA), una pandemia con altos costos económicos y sociales. La glicoproteína de la envoltura (ENV) del virus media el proceso infeccioso al unirse a la célula huésped y entrar en ella, uno de los principales componentes objetivo de los estudios desde su descubrimiento. Su endodominio o cola C-terminal (CTT) participa en procesos tardíos del ciclo replicativo, como tráfico intracelular, activación y muerte celular, lo que ocurre porque interactúa con múltiples factores celulares a través de motivos o secuencias señal presentes en toda su estructura. Aunque estas interacciones no se han entendido completamente a niveles específicos, los estudios durante más de tres décadas no dejan dudas de que este campo juega un papel fundamental en la biología del virus y probablemente en el desarrollo de la enfermedad. Esta revisión describe los estudios realizados hasta la fecha que demuestran la importancia de la CTT, centrándose en los motivos responsables de sus interacciones y sus posibles roles en la patogenicidad de la infección.

Resumo: o vírus da imunodeficiência humana tipo 1 (HIV-1) é o agente etiológico da síndrome da imunodeficiência adquirida (AUXILIA), urna pandemia com elevados custos económicos e sociais. A glicoproteína do envelope (ENV) do vírus media o processo infeccioso ligando-se e entrando na célula hospedeira, um dos principais componentes alvo dos estudos desde sua descoberta. Seu endo domínio ou cauda C-terminal (CTT) participa de processos do ciclo replicativo tardio, como tráfego intracelular, ativação e morte celular, que ocorre porque interage com múltiplos fatores celulares por meio de motivos ou sequências-sinal presentes em toda a sua estrutura. Embora essas interações não tenham sido totalmente compreendidas em níveis específicos, estudos ao longo de mais de três décadas não deixam dúvidas de que esse domínio desempenha um papel fundamental na biologia do vírus e provavelmente no desenvolvimento da doença. Esta revisão descreve os estudos realizados até o momento que demonstram a importância da CTT, com foco nos motivos responsáveis por suas interações e seus possíveis papéis na patogenicidade da infecção.

Presence of Pathogenic Leptospira spp. in an Urban Slum of the Colombian Caribbean: A One Health Approach

Introducción: La leptospirosis es una zoonosis que tiene alto impacto en la salud de las personas y los animales, especialmente en áreas tropicales y subtropicales. Esta enfermedad es causada por el patógeno Leptospira spp. y es transmitida principalmente por los roedores. Objetivo: Describir la presencia de Leptospira patógena y los posibles factores de riesgo de leptospirosis en un sector marginal de Colombia, con un enfoque One-Health. Métodos: Se llevó acabo un estudio exploratorio en un sector marginal de Soledad, municipio situado en la costa norte de Colombia. Se tomaron muestras de sangre de 83 sujetos. Se analizaron variables sociodemográficas, clínicas y ecológicas relacionadas con la leptospirosis. La presencia de anticuerpos IgM anti-leptospira en el suero humano fue detectado mediante la prueba ELISA. También, se tomaron muestras de tejido renal de 53 roedores sinantrópicos para identificar Leptospira spp. patógenas mediante PCR convencional a través del uso de cebadores específicos. Resultados: Se detectaron anticuerpos IgM-anti-leptospira en el 30,12 por ciento de los sujetos de estudio. La Leptospira spp. patógena fue identificada en el 7,55 por ciento de los roedores analizados. En la muestra seleccionada se encontró asociación de casos seropositivos con ser comerciantes, ama de casa y estar en contacto con cerdos. Las condiciones higiénico-sanitarias subóptimas también fueron evidentes en el área de estudio. Conclusiones: La circulación de Leptospira spp. patógena y la exposición a factores de riesgo humanos y ecológicos es elevada en el sector marginal (área de pobreza) del Caribe colombiano. Se recomienda dirigir las intervenciones en la interfaz hombre-animal-ambiente de acuerdo con el paradigma One-Health; se debe considerar la extrema pobreza como un factor determinante para la ocurrencia de la leptospirosis(AU)

Objective: This study aims to describe the presence of pathogenic Leptospira and potential risk factors for leptospirosis in a marginal sector of the Colombian Caribbean, with a One Health approach. Methods: an exploratory study was carried out in a marginal sector of Soledad, a municipality located in the north coast of Colombia. Blood samples were taken from 83 subjects, who were also questioned about sociodemographic, clinical and ecological variables related to leptospirosis. The presence of IgM Anti-Leptospira antibodies in human serum was performed by ELISA. A total 53 synanthropic rodents were also captured using Sherman traps. Renal tissue samples were taken from rodents to identify pathogen Leptospira spp. by conventional PCR using specific primers. Results: IgM-anti-Leptospira was present in 30.12 percent of study subjects and pathogenic Leptospira spp. was identified in 7.55 percent of captured rodents. In the selected sample we found an association of positive cases with being a merchant, housewife and being in contact with pigs. Suboptimal hygienic-sanitary conditions were also evident in the study area. Conclusions: Our results show the circulation of pathogenic Leptospira spp. and exposure to human and ecological risk factors in a marginal sector (slum) of the Colombian Caribbean. We suggest to direct interventions in the human-animal-environment interface according to the One Health paradigm, considering extreme poverty as a determining factor for Leptospirosis occurrence(AU)

Distribution of polymorphism rs693 of ApoB gene in a sample of Colombian Caribbeans / Distribución del polimorfismo rs693 en el gen de la apolipoproteína B en una muestra caribeños colombianos

Abstract Introduction: Several studies have reported that the single nucleotide polymorphism rs693 of Apo lipoprotein B gene is associated with high levels of plasma lipids and high body mass index, which are risk factors for cardiovascular diseases. The distribution of this single nucleotide polymorphism and its association with the phenotype depend on the genetic background of each population. Objective: To evaluate the distribution of single nucleotide polymorphism rs693 and its association with lipid profile and body mass index in a sample of Colombian Caribbeans. Methods: 108 non-related adult subjects of both gender were included in this study. Body mass index and lipid profile that included total cholesterol, triglycerides, Low Density Lipoprotein and High Density Lipoprotein were determined. The single nucleotide polymorphism rs693 was determined by Polymerase Chain Reaction/Restriction Fragment Length Polymorphism from genomic DNA followed by digestion with the restriction enzyme XbaI. The chi-square test was used to analyze the genotype distribution of rs693 and the genotype-phenotype association was evaluated through different inheritance model. Results: The genotype frequencies for single nucleotide polymorphism rs693 were CC (45.0%), TT (16.5%) and CT (38.5%). The allele frequencies were C (64.0%) and T (36.0%). The single nucleotide polymorphism was in Hardy-Weinberg equilibrium in the studied sample. No association of the single nucleotide polymorphism rs693 with lipid profile nor the body mass index was found (p >0.05). Conclusion: There is no significant association between single nucleotide polymorphism rs693 and body mass index nor lipid profile, in a sample of Colombian Caribbeans.

Resumen Introducción: Varios estudios han informado que el polimorfismo de un solo nucleótido rs693 del gen de la apolipoproteína B se asocia con altos niveles de lípidos plasmáticos e índice de masa corporal, los cuales son factores de riesgo para enfermedades cardiovasculares. La distribución de este polimorfismo y su asociación con el fenotipo dependen del antecedente genético de cada población. La población caribeña colombiana es producto de la mezcla de tres grupos étnicos principales: africano, amerindio y caucásico. Objetivo: Evaluar la distribución del polimorfismo rs693 y su asociación con el perfil lipídico y el índice de masa corporal en una muestra de sujetos caribeños colombianos. Métodos: Fueron incluidos en este estudio 108 sujetos adultos de ambos sexos y no relacionados. Se determinaron el índice de masa corporal y el perfil lipídico; de éste se incluyó colesterol total, triglicéridos, lipoproteínas de baja densidad y lipoproteína de alta densidad. El polimorfismo rs693 se determinó mediante Reacción en Cadena de la Polimerasa del ADN genómico seguida por digestión con la enzima de restricción XbaI. Se utilizó la prueba de ji cuadrado para analizar la distribución del genotipo de rs693 y se evaluó la asociación genotipo-fenotipo a través de diferentes modelos de herencia. Resultados: Las frecuencias genotípicas para rs693 fueron CC (45.0%), TT (16.5%) y TC (38.5%). Las frecuencias alélicas fueron C (64.0%) y T (36.0%). El polimorfismo rs693 estaba en equilibrio de Hardy-Weinberg en la muestra estudiada y no presentó asociación con el perfil lipídico ni con el índice de masa corporal (p >0.05). Conclusión: No existe asociación significativa del polimorfismo rs693 con el índice de masa corporal ni con el perfil lipídico en una muestra de caribeños colombianos.

Distribution of polymorphism rs693 of ApoB gene in a sample of Colombian Caribbeans.

INTRODUCTION: Several studies have reported that the single nucleotide polymorphism rs693 of Apo lipoprotein B gene is associated with high levels of plasma lipids and high body mass index, which are risk factors for cardiovascular diseases. The distribution of this single nucleotide polymorphism and its association with the phenotype depend on the genetic background of each population. OBJECTIVE: To evaluate the distribution of single nucleotide polymorphism rs693 and its association with lipid profile and body mass index in a sample of Colombian Caribbeans. METHODS: 108 non-related adult subjects of both gender were included in this study. Body mass index and lipid profile that included total cholesterol, triglycerides, Low Density Lipoprotein and High Density Lipoprotein were determined. The single nucleotide polymorphism rs693 was determined by Polymerase Chain Reaction/Restriction Fragment Length Polymorphism from genomic DNA followed by digestion with the restriction enzyme XbaI. The chi-square test was used to analyze the genotype distribution of rs693 and the genotype-phenotype association was evaluated through different inheritance model. RESULTS: The genotype frequencies for single nucleotide polymorphism rs693 were CC (45.0%), TT (16.5%) and CT (38.5%). The allele frequencies were C (64.0%) and T (36.0%). The single nucleotide polymorphism was in Hardy-Weinberg equilibrium in the studied sample. No association of the single nucleotide polymorphism rs693 with lipid profile nor the body mass index was found (p >0.05). CONCLUSION: There is no significant association between single nucleotide polymorphism rs693 and body mass index nor lipid profile, in a sample of Colombian Caribbeans.

INTRODUCCIÓN: Varios estudios han informado que el polimorfismo de un solo nucleótido rs693 del gen de la apolipoproteína B se asocia con altos niveles de lípidos plasmáticos e índice de masa corporal, los cuales son factores de riesgo para enfermedades cardiovasculares. La distribución de este polimorfismo y su asociación con el fenotipo dependen del antecedente genético de cada población. La población caribeña colombiana es producto de la mezcla de tres grupos étnicos principales: africano, amerindio y caucásico. OBJETIVO: Evaluar la distribución del polimorfismo rs693 y su asociación con el perfil lipídico y el índice de masa corporal en una muestra de sujetos caribeños colombianos. MÉTODOS: Fueron incluidos en este estudio 108 sujetos adultos de ambos sexos y no relacionados. Se determinaron el índice de masa corporal y el perfil lipídico; de éste se incluyó colesterol total, triglicéridos, lipoproteínas de baja densidad y lipoproteína de alta densidad. El polimorfismo rs693 se determinó mediante Reacción en Cadena de la Polimerasa del ADN genómico seguida por digestión con la enzima de restricción XbaI. Se utilizó la prueba de ji cuadrado para analizar la distribución del genotipo de rs693 y se evaluó la asociación genotipo-fenotipo a través de diferentes modelos de herencia. RESULTADOS: Las frecuencias genotípicas para rs693 fueron CC (45.0%), TT (16.5%) y TC (38.5%). Las frecuencias alélicas fueron C (64.0%) y T (36.0%). El polimorfismo rs693 estaba en equilibrio de Hardy-Weinberg en la muestra estudiada y no presentó asociación con el perfil lipídico ni con el índice de masa corporal (p >0.05). CONCLUSIÓN: No existe asociación significativa del polimorfismo rs693 con el índice de masa corporal ni con el perfil lipídico en una muestra de caribeños colombianos.

Análisis de los polimorfismos europeos en el gen lactasa entre grupos étnicos del Caribe Colombiano / Analysis of the european polymorphisms in lactase gene between ethnic groups in the Colombian Caribbean / Análise dos polimorfismos europeus no gene lactasa entre os grupos etnicos do Caribe Colombiano

La prevalencia de hipolactasia tipo adulto está influenciada por la etnicidad y la geografía. Los genotipos CC y GG, de los SNPs C/T-13910 y G/A-22018, respectivamente determinan hipolactasia en ciertos grupos étnicos y países del mundo. El objetivo de este estudio fue analizar estos SNPs en muestras de los tres grupos étnicos que habitan el Caribe Colombiano. Trescientos sesenta y un sujetos, agrupados como afrodescendientes, indígenas y mestizos, fueron genotipificados usando PCR/RFLP. El análisis genético se hizo mediante Arlequin 3.11 y las frecuencias genotípicas fueron comparadas con Statgraphics Centurion XVI. Solamente el SNP C/T-13910 mostró equilibrio de Hardy- Weinberg y no hubo desequilibrio de ligamiento entre los SNPs estudiados. La frecuencia del genotipo CC-13910 fue 90% en afrodescendientes, 95% en indígenas y 80% en mestizos. En indígenas la frecuencia de GG-22018 fue 23% pero dicho genotipo no se halló en afrodescendientes y mestizos. El genotipo AA-22018 no se halló en indígenas. Ningún grupo presentó el genotipo TT-13910. Las frecuencias genotípicas fueron estadísticamente diferentes entre los grupos estudiados y las de los genotipos CC-13910 y GG-22018 no concordaron con las frecuencias fenotípicas reportadas en otros estudios. Los resultados sugieren que la posibilidad diagnóstica de hipolactasia mediante genotipificación de estos polimorfismos es escasa en el Caribe Colombiano.

The prevalence of adult-type hypolactasia is influenced by ethnicity and geography. The CC and GG genotypes of the SNPs C/T-13910 and G/A-22018, respectively indicate hypolactasia in certain ethnic groups worldwide. The aim of this study was to analyse these SNPs in samples of the three ethnic groups that inhabit the Colombian Caribbean. Three hundred and sixty-one subjects were genotyped using PCR/RFLP. These subjects were grouped as being of African descent, Indigenous and Mestizo. The genetic analysis was performed through Arlequin 3.11 and genotype frequencies were compared with Statgraphics Centurion XVI. Only SNP C/T-13910 showed Hardy-Weinberg equilibrium and there was no linkage disequilibrium between the SNPs. The frequency of CC-13910 was 90% in Afro-descendant, 95% in indigenous people and 80% in mestizos.The frequency of GG-22018 was 23% in indigenous people, but this genotype was not present in afro-descendants and Mestizos. The indigenous people did not have AA-22018, and none of the groups had TT-13910. The genotype frequencies were statistically different among the groups studied and the frequencies of CC-13910 and GG-22018 were not in concordance with the phenotype frequencies reported in other papers. The results suggest that diagnostic possibility of hypolactasia by genotyping of those polymorphisms in the Colombian Caribbean population is scarce.

A prevalência da hipolactasia primária tipo adulto é influenciada pela etnicidade e a geografia. Os genótipos CC e GG, dos SNPs C/T-13910 e G/A-22018, respectivamente, são determinantes da hipolactasia em alguns grupos étnicos e países do mundo. O objetivo do presente estudo foi analisar estes SNPs em amostras dos três grupos étnicos do Caribe Colombiano. Trezentas e sessenta e uma pessoas reunidas como afrodescendentes, indígenas e mestiços foram genotipificadas utilizando PCR/RFLP. A análise genética foi realizada usando o software Arlequin 3.11 e as frequências genotípicas foram comparadas com o Statgraphics Centurion XVI. Somente o SNP C/T-13910 mostrou equilíbrio de Hardy-Weinberg e não houve desequilíbrio de ligamento entre os SNPs estudados. A frequência do genótipo CC-13910 foi de 90% para afrodescendentes, 95% para indígenas e 80% em mestiços. Nos indígenas a frequência de GG-22018 foi de 23% mas tal genótipo não esteve presente na população de afrodescendentes e mestiços. O genótipo AA-22018 não foi encontrado em indígenas. Nenhum grupo apresentou o genótipo TT-13910. As frequências genotípicas foram estatisticamente diferentes entre os grupos avaliados e as dos genótipos CC-13910 e GG-22018, não concordaram com as frequências fenotípicas relatados em outros estudos. Os resultados sugerem que a possibilidade diagnóstica de hipolactasia através de genotipificação destes polimorfismos é escassa em populações do Caribe Colombiano.

Análisis de los polimorfismos europeos en el gen Lactasa entre grupos étnicos del Caribe Colombiano / Analysis of the European polymorphisms in lactase gene between ethnic groups in the Colombian Caribbean / Análise dos polimorfismos europeus no gene lactasa entre os grupos etnicos do Caribe Colombiano

La prevalencia de hipolactasia tipo adulto está influenciada por la etnicidad y la geografía. Los genotipos CC y GG, de los SNPs C/T-13910 y G/A-22018, respectivamente determinan hipolactasia en ciertos grupos étnicos y países del mundo. El objetivo de este estudio fue analizar estos SNPs en muestras de los tres grupos étnicos que habitan el Caribe Colombiano. Trescientos sesenta y un sujetos, agrupados como afrodescendientes, indígenas y mestizos, fueron genotipificados usando PCR/RFLP. El análisis genético se hizo mediante Arlequin 3.11 y las frecuencias genotípicas fueron comparadas con Statgraphics Centurion XVI. Solamente el SNP C/T-13910 mostró equilibrio de Hardy- Weinberg y no hubo desequilibrio de ligamiento entre los SNPs estudiados. La frecuencia del genotipo CC-13910 fue 90% en afrodescendientes, 95% en indígenas y 80% en mestizos. En indígenas la frecuencia de GG-22018 fue 23% pero dicho genotipo no se halló en afrodescendientes y mestizos. El genotipo AA-22018 no se halló en indígenas. Ningún grupo presentó el genotipo TT-13910. Las frecuencias genotípicas fueron estadísticamente diferentes entre los grupos estudiados y las de los genotipos CC-13910 y GG-22018 no concordaron con las frecuencias fenotípicas reportadas en otros estudios. Los resultados sugieren que la posibilidad diagnóstica de hipolactasia mediante genotipificación de estos polimorfismos es escasa en el Caribe Colombiano.(AU)

The prevalence of adult-type hypolactasia is influenced by ethnicity and geography. The CC and GG genotypes of the SNPs C/T-13910 and G/A-22018, respectively indicate hypolactasia in certain ethnic groups worldwide. The aim of this study was to analyse these SNPs in samples of the three ethnic groups that inhabit the Colombian Caribbean. Three hundred and sixty-one subjects were genotyped using PCR/RFLP. These subjects were grouped as being of African descent, Indigenous and Mestizo. The genetic analysis was performed through Arlequin 3.11 and genotype frequencies were compared with Statgraphics Centurion XVI. Only SNP C/T-13910 showed Hardy-Weinberg equilibrium and there was no linkage disequilibrium between the SNPs. The frequency of CC-13910 was 90% in Afro-descendant, 95% in indigenous people and 80% in mestizos.The frequency of GG-22018 was 23% in indigenous people, but this genotype was not present in afro-descendants and Mestizos. The indigenous people did not have AA-22018, and none of the groups had TT-13910. The genotype frequencies were statistically different among the groups studied and the frequencies of CC-13910 and GG-22018 were not in concordance with the phenotype frequencies reported in other papers. The results suggest that diagnostic possibility of hypolactasia by genotyping of those polymorphisms in the Colombian Caribbean population is scarce.(AU)

A prevalÛncia da hipolactasia primária tipo adulto é influenciada pela etnicidade e a geografia. Os genótipos CC e GG, dos SNPs C/T-13910 e G/A-22018, respectivamente, sÒo determinantes da hipolactasia em alguns grupos étnicos e países do mundo. O objetivo do presente estudo foi analisar estes SNPs em amostras dos trÛs grupos étnicos do Caribe Colombiano. Trezentas e sessenta e uma pessoas reunidas como afrodescendentes, indígenas e mestiþos foram genotipificadas utilizando PCR/RFLP. A análise genética foi realizada usando o software Arlequin 3.11 e as frequÛncias genotípicas foram comparadas com o Statgraphics Centurion XVI. Somente o SNP C/T-13910 mostrou equilíbrio de Hardy-Weinberg e nÒo houve desequilíbrio de ligamento entre os SNPs estudados. A frequÛncia do genótipo CC-13910 foi de 90% para afrodescendentes, 95% para indígenas e 80% em mestiþos. Nos indígenas a frequÛncia de GG-22018 foi de 23% mas tal genótipo nÒo esteve presente na populaþÒo de afrodescendentes e mestiþos. O genótipo AA-22018 nÒo foi encontrado em indígenas. Nenhum grupo apresentou o genótipo TT-13910. As frequÛncias genotípicas foram estatisticamente diferentes entre os grupos avaliados e as dos genótipos CC-13910 e GG-22018, nÒo concordaram com as frequÛncias fenotípicas relatados em outros estudos. Os resultados sugerem que a possibilidade diagnóstica de hipolactasia através de genotipificaþÒo destes polimorfismos é escassa em populaþ§es do Caribe Colombiano.(AU)

The use of factorial design, image analysis, and an efficiency calculation for multiplex PCR optimization.

BACKGROUND: The quality of multiplex polymerase chain reaction (PCR) assays depends on several factors. Therefore, it is important to establish the optimal conditions to achieve efficient amplification. The objective of this study was to implement a 5 × 4 factorial design combined with image analysis using agarose gels and an efficiency calculation to optimize a multiplex PCR assays for the detection of Salmonella enterica serovar typhimurium. METHODS: We used 12 ng of Salmonella DNA obtained from pure cultures and applied different annealing temperatures (65°C, 64.5°C, 63.3°C, 61.4°C, or 59°C) and different MgCl2 concentrations (1 mM, 1.5 mM, 2 mM, or 2.5 mM) to amplify regions of the fliC, rfbJ, and fljB genes. The 5 × 4 factorial design was performed using Statgraphics Plus software version 5.1, and the images were analyzed using Image Lab(TM) software. RESULTS: Superior amplification was obtained using an annealing temperature of 65°C and 2 mM MgCl2 . This finding was confirmed by calculating the efficiency of multiplex PCR assays (6.1%) at these conditions. CONCLUSION: We propose the application of factorial design and image analysis to determine the most suitable conditions for multiplex PCR optimization.

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.

CONTEXT: Genotyping of single nucleotide polymorphism (SNP C/T(-13910)) located upstream of the lactase gene is used to determine adult-type hypolactasia/lactase persistence in North-European Caucasian subjects. The applicability of this polymorphism has been studied by comparing it with the standard diagnostic methods in different populations. OBJECTIVE: To compare the lactose hydrogen breath test with the genetic test in a sample of the Colombian Caribbean population. METHODS: Lactose hydrogen breath test and genotyping of SNP C/T(-13910) were applied to 128 healthy individuals (mean age 35 ± 1). A positive lactose hydrogen breath test was indicative of hypolactasia. Genotyping was done using polymerase chain reaction/restriction fragment length polymorphism. The kappa index was used to establish agreement between the two methods. RESULTS: Seventy-six subjects (59%) were lactose-maldigesters (hypolactasia) and 52 subjects (41%) were lactose-digesters (lactase persistence). The frequencies of the CC, CT and TT genotypes were 80%, 20% and 0%, respectively. Genotyping had 97% sensitivity and 46% specificity. The kappa index = 0.473 indicates moderate agreement between the genotyping of SNP C/T(-13910) and the lactose hydrogen breath test. CONCLUSION: The moderate agreement indicates that the genotyping of the SNP C/T(-13910) is not applicable to determine adult-type hypolactasia/lactase persistence in the population participating in this study.

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 / Diagnóstico de hipolactasia tipo adulto/persistência da lactase: a genotipagem do polimorfismo de um único nucleotídeo (SNP) C/T-13910 não é consistente com o teste de hidrogênio na população do Caribe Colombiano

CONTEXT: Genotyping of single nucleotide polymorphism (SNP C/T-13910) located upstream of the lactase gene is used to determine adult-type hypolactasia/lactase persistence in North-European Caucasian subjects. The applicability of this polymorphism has been studied by comparing it with the standard diagnostic methods in different populations. OBJECTIVE: To compare the lactose hydrogen breath test with the genetic test in a sample of the Colombian Caribbean population. METHODS: Lactose hydrogen breath test and genotyping of SNP C/T-13910 were applied to 128 healthy individuals (mean age 35 ± 1). A positive lactose hydrogen breath test was indicative of hypolactasia. Genotyping was done using polymerase chain reaction/restriction fragment length polymorphism. The kappa index was used to establish agreement between the two methods. RESULTS: Seventy-six subjects (59%) were lactose-maldigesters (hypolactasia) and 52 subjects (41%) were lactose-digesters (lactase persistence). The frequencies of the CC, CT and TT genotypes were 80%, 20% and 0%, respectively. Genotyping had 97% sensitivity and 46% specificity. The kappa index = 0.473 indicates moderate agreement between the genotyping of SNP C/T-13910 and the lactose hydrogen breath test. CONCLUSION: The moderate agreement indicates that the genotyping of the SNP C/T-13910 is not applicable to determine adult-type hypolactasia/lactase persistence in the population participating in this study.

CONTEXTO: A genotipagem do SNP C/T-13910 localizado corrente acima do gene da lactase é usada para determinar hipolactasia e persistência da lactase tipo adulto em indivíduos caucasianos do Norte da Europa. A aplicabilidade deste polimorfismo tem sido estudada em comparação com métodos padronizados de diagnóstico em diferentes populações. OBJETIVO: Comparar o teste de hidrogênio expirado após a ingestão de lactose com o teste genético em uma mostra da população do Caribe Colombiano. MÉTODOS: O teste de hidrogênio expirado após a ingestão de lactose e a genotipagem do SNP C/T-13910 foram aplicados em 128 sujeitos sadios (idade media 35 ± 1). O teste de hidrogênio positivo foi indicativo de hipolactasia. A genotipagem foi feita pelo método "polymerase chain reaction/restriction fragment length polymorphism". O índice Kappa foi utilizado para estabelecer a concordância entre os dois métodos. RESULTADOS: Setenta e seis indivíduos (59%) foram mau digestores da lactose (hipolactasia) e 52 outros (41%) foram digestores da lactose (persistência da lactase). As frequências dos genotipos CC, CT e TT foram 80%, 20% e 0%, respectivamente. A genotipagem mostrou 97% da sensibilidade e 46% da especificidade. O índice kappa: 0,473 indicou moderada concordância entre os dois métodos. CONCLUSÃO: A moderada concordância indica que a genotipagem do SNP C/T-13910 nao é aplicável para determinar hipolactasia tipo adulto/persistência da lactase na população estudada.