RESUMEN
Because there is reason to believe that genetic variants could account for different treatment responses in subjects with asthma, it is important to collect blood for genetic-analysis purposes when conducting clinical trials in asthma. This article describes issues related to maintaining subject confidentiality, tracking and shipping blood samples, quality control procedures at the laboratory performing the genotyping, and necessary data verification checks when implementing the genetic-analysis database for the Asthma Clinical Research Network.
Asunto(s)
Albuterol/análogos & derivados , Asma/genética , Ensayos Clínicos como Asunto/métodos , Comités de Ética en Investigación , Agonistas Adrenérgicos beta/uso terapéutico , Albuterol/uso terapéutico , Asma/tratamiento farmacológico , Confidencialidad , Genotipo , Humanos , Control de Calidad , Xinafoato de SalmeterolRESUMEN
Recent family-based studies have revealed evidence for linkage of chromosomal region 12q to both asthma and high total serum immunoglobulin E (IgE) levels. Among the candidate genes in this region for asthma is neuronal nitric oxide synthase (NOS1). We sought a genetic association between a polymorphism in the NOS1 gene and the diagnosis of asthma, using a case-control design. Frequencies for allele 17 and 18 of a CA repeat in exon 29 of the NOS1 gene were significantly different between 490 asthmatic and 350 control subjects. Allele 17 was more common in the asthmatics (0.83 vs 0.76, or 1.49 [95% CI 1.17-1.90], P = 0.013) while allele 18 was less common in the asthmatics (0.06 vs 0.12, or 0.49 [95% CI 0.34-0. 69], P = 0.0004). To confirm these results we genotyped an additional 1131 control subjects and found the frequencies of alleles 17 and 18 to be virtually identical to those ascertained in our original control subjects. Total serum IgE was not associated with any allele of the polymorphism. These findings provide support, from case-control association analysis, for NOS1 as a candidate gene for asthma.
Asunto(s)
Asma/enzimología , Asma/genética , Óxido Nítrico Sintasa/genética , Polimorfismo Genético/genética , Adulto , Anciano , Anciano de 80 o más Años , Alelos , Asma/inmunología , Estudios de Casos y Controles , Repeticiones de Dinucleótido/genética , Exones/genética , Frecuencia de los Genes/genética , Genotipo , Humanos , Inmunoglobulina E/sangre , Modelos Logísticos , Masculino , Persona de Mediana Edad , Modelos Genéticos , Óxido Nítrico Sintasa de Tipo I , Oportunidad Relativa , Estados Unidos , Población Blanca/genéticaRESUMEN
Suppressor of cytokine signaling (SOCS) proteins are involved in the negative regulation of cytokine-induced STAT (signal transducers and activators of transcription) factor signaling. We cloned genomic regions of SOCS1 and SOCS2 genes and mapped these genes to chromosome 16p12-p13.1 and chromosome 12q21.3-q23 regions, respectively, by cytogenetic and radiation hybrid mapping. In addition, we mapped SOCS2 by yeast artificial chromosome (YAC) pool screening to YAC contig WC 12.5 on chromosome 12 with an unambiguous hit to CHLC.ATA19H12 and WI-5940, which is 461.5 cR from the top of the map.
Asunto(s)
Proteínas Portadoras/genética , Cromosomas Humanos Par 12 , Cromosomas Humanos Par 16 , Proteínas de Unión al ADN , Péptidos y Proteínas de Señalización Intracelular , Proteínas/genética , Proteínas Represoras , Transactivadores , Mapeo Cromosómico , Cromosomas Artificiales de Levadura , Clonación Molecular , Citocinas/metabolismo , Humanos , Células Híbridas , Hibridación Fluorescente in Situ , Transducción de Señal , Proteína 1 Supresora de la Señalización de Citocinas , Proteínas Supresoras de la Señalización de CitocinasRESUMEN
Recent family-based studies have revealed evidence for linkage of human chromosome 5q31 to the diagnosis of asthma, elevated serum IgE levels, and bronchial hyperresponsiveness. Among the candidate genes in this region is the gene encoding for human interleukin-4 (IL-4). We reasoned that this gene could also serve as a candidate gene with respect to asthma severity as indicated by the FEV(1) measured when bronchodilator treatment was withheld. To test this hypothesis, we examined a large population of patients with asthma (ascertained without respect to genetic characteristics), for associations between a genetic variant in the IL-4 promoter region (C-589T) and asthma severity, as indicated by FEV(1). We used amplification by the polymerase chain reaction followed by BsmF1 restriction digestion to assign genotypes at the IL-4 promoter C-589T locus. We compared genotypes at this locus in 772 Caucasian and African American patients with asthma of varying severity, and we used multiple regression analysis to relate genotypic findings to FEV(1). Among white individuals, the homozygous presence of the C-589T IL-4 promoter genotype (TT) was associated with a FEV(1) below 50% of predicted (p = 0.013; OR, 1.44; 95% CI: 1.09 to 1.90). Subjects with the TT genotype had mean FEV(1) (% predicted) values 4.5% lower than those of subjects with the wild-type (CC) genotype at this locus. FEV(1) values of white patients with a CC or CT genotype were broadly distributed, whereas the TT genotype was associated with a narrow distribution of low FEV(1) values. The frequency of the T allele was significantly greater (p = 1 x 10(-)(23)) among African American asthmatics (0.544) than among white asthmatics (0.183). These data provide the first evidence associating FEV(1) in patients with asthma and genetic determinants at any locus. Our data are consistent with the idea that the FEV(1) in asthma is the result of multiple factors; one of these factors is the genotype at the IL-4 C-589T locus. This locus is associated with a small but significant decrement in pulmonary function among white asthmatic subjects.
Asunto(s)
Asma/genética , Volumen Espiratorio Forzado , Genes/genética , Interleucina-4/genética , Adulto , Alelos , Asma/sangre , Asma/fisiopatología , Estudios de Cohortes , Interpretación Estadística de Datos , Femenino , Frecuencia de los Genes , Genotipo , Humanos , Inmunoglobulina E/sangre , Masculino , Reacción en Cadena de la Polimerasa , Regiones Promotoras Genéticas/genéticaRESUMEN
Clinically similar asthma patients may develop airway obstruction by different mechanisms. Asthma treatments that specifically interfere with the 5-lipoxygenase (ALOX5) pathway provide a method to identify those patients in whom the products of the ALOX5 pathway (that is, the leukotrienes) contribute to the expression of the asthma phenotype. Failure of an asthma patient to respond to treatment with ALOX5-pathway modifiers indicates that leukotrienes are not critical to the expression of the asthmatic phenotype in that patient. We previously defined a family of DNA sequence variants in the core promoter of the gene ALOX5 (on chromosome 10q11.2) associated with diminished promoter-reporter activity in tissue culture. Because expression of ALOX5 is in part transcriptionally regulated, we reasoned that patients with these sequence variants may have diminished gene transcription, and therefore decreased ALOX5 product production and a diminished clinical response to treatment with a drug targeting this pathway. Such an effect indicates an interaction between gene promoter sequence variants and drug-treatment responses, that is, a pharmacogenetic effect of a promoter sequence on treatment responses.
Asunto(s)
Antiasmáticos/uso terapéutico , Araquidonato 5-Lipooxigenasa/genética , Asma/tratamiento farmacológico , Asma/genética , Hidroxiurea/análogos & derivados , Regiones Promotoras Genéticas , Alelos , Asma/enzimología , Frecuencia de los Genes , Variación Genética , Humanos , Hidroxiurea/uso terapéutico , Inhibidores de la Lipooxigenasa/uso terapéutico , Fenotipo , Resultado del TratamientoRESUMEN
Allelic frequencies of a CA dinucleotide repeat in exon 29 and an intronic AAT trinucleotide repeat in the neuronal nitric oxide synthase (NOS1) gene were determined by simple sequence length polymorphism (SSLP) in 305 American-Caucasian and 105 African-American healthy subjects. There were highly significant differences in allele frequencies between the two ethnically diverse study populations.
Asunto(s)
Población Negra/genética , Óxido Nítrico Sintasa/genética , Secuencias Repetidas en Tándem/genética , Población Blanca/genética , Alelos , Distribución de Chi-Cuadrado , ADN/química , ADN/genética , Frecuencia de los Genes , Humanos , Datos de Secuencia Molecular , Óxido Nítrico Sintasa de Tipo I , Polimorfismo Genético , Análisis de Secuencia de ADN , Estados UnidosRESUMEN
Arachidonate 5-lipoxygenase-activating protein (ALOX5AP) is an arachidonic acid binding protein that has been shown to be critical in the biosynthesis of leukotrienes. We mapped the ALOX5AP gene to the chromosome 13q12 region by cytogenetic mapping, yeast artificial chromosome (YAC) pool screening, and radiation hybrid mapping. It was mapped to YAC contig WC13.2 by YAC pool screening with an unambiguous hit to WI-4874, which is at 78 cR on the radiation hybrid map, 3.36 cR, by radiation hybrid mapping, from WI-4874.
Asunto(s)
Proteínas Portadoras/genética , Cromosomas Humanos Par 13/genética , Proteínas de la Membrana/genética , Proteínas Activadoras de la 5-Lipooxigenasa , Humanos , Hibridación in Situ , Leucotrienos/genética , Mapeo Físico de Cromosoma/métodosRESUMEN
Five lipoxygenase (5-LO) is the first committed enzyme in the metabolic pathway leading to the synthesis of the leukotrienes. We examined genomic DNA isolated from 25 normal subjects and 31 patients with asthma (6 of whom had aspirin-sensitive asthma) for mutations in the known transcription factor binding regions and the protein encoding region of the 5-LO gene. A family of mutations in the G + C-rich transcription factor binding region was identified consisting of the deletion of one, deletion of two, or addition of one zinc finger (Sp1/Egr-1) binding sites in the region 176 to 147 bp upstream from the ATG translation start site where there are normally 5 Sp1 binding motifs in tandem. Reporter gene activity directed by any of the mutant forms of the transcription factor binding region was significantly (P < 0.05) less effective than the activity driven by the wild type transcription factor binding region. Electrophoretic mobility shift assays (EMSAs) demonstrated the capacity of wild type and mutant transcription factor binding regions to bind nuclear extracts from human umbilical vein endothelial cells (HUVECs). These data are consistent with a family of mutations in the 5-LO gene that can modify reporter gene transcription possibly through differences in Sp1 and Egr-1 transactivation.