title: HMOX1 promoter (GT)n polymorphim is associated with childhood-onset systemic lupus erythematosus but not with juvenile rheumatoid arthritis in a Mexican population.
abstract: OBJECTIVE
  The heme oxigenase 1 (HO-1), a rate-limiting enzyme for heme degradation, is an important cytoprotective protein. Transcriptional activity of HO-1 coding gene (HMOX1) can be regulated by the presence of a dinucleotide repeat polymorphism (GT)n at its promoter region. Accordingly, length of (GT)n repeat has been associated with susceptibility to several diseases. We investigated whether the HMOX1 (GT)n polymorphism was associated with childhood-onset systemic lupus erythematosus (SLE) and juvenile rheumatoid arthritis (JRA) susceptibility.
  
  
  METHODS
  We studied 207 and 333 unrelated Mexican patients with JRA and childhood-onset SLE, respectively. The control population consisted of 653 individuals ethnically matched with cases. The HMOX1 (GT)n polymorphism was genotype by PCR and fluorescence technology.
  
  
  RESULTS
  We found 27 different alleles, with the 22 and 29 repeats as the most common alleles. Distribution of short allele (n<25) and SS genotype was not statistically associated with JRA subjects. Interestingly, the frequency of both short allele and SS genotype was significantly associated with SLE susceptibility (OR=1.47, 95%CI [1.14-1.89], p=0.002; and OR=2.79, 95%CI [1.24-6.24], p=0.01, respectively).
  
  
  CONCLUSIONS
  The distribution pattern of HMOX1 (GT) alleles was different in the Mexican population than those reported elsewhere. Our results suggest that HMOX1 (GT)n polymorphism was associated with susceptibility to childhood-onset SLE but not with JRA in Mexican individuals.
authors.affiliation: Immunogenomics and Metabolic Disease Laboratory, Instituto Nacional de Medicina Genómica, SS, Mexico City, Mexico City, Mexico. ecordova@inmegen.gob.mx
authors.forename: Emilio J
authors.initials: EJ
authors.lastname: Córdova
authors.forename: Angélica
authors.initials: A
authors.lastname: Martínez-Hernández
authors.forename: Julian
authors.initials: J
authors.lastname: Ramírez-Bello
authors.forename: Rafael
authors.initials: R
authors.lastname: Velázquez-Cruz
authors.forename: Federico
authors.initials: F
authors.lastname: Centeno
authors.forename: Vicente
authors.initials: V
authors.lastname: Baca
authors.forename: Lorena
authors.initials: L
authors.lastname: Orozco
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D001171:Arthritis, Juvenile / Q000201:enzymology / Q000453:epidemiology / Q000235:genetics*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002648:Child; D018900:Dinucleotide Repeats; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D051547:Heme Oxygenase-1 / Q000235:genetics*; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000201:enzymology / Q000453:epidemiology / Q000235:genetics*; D008297:Male; D008800:Mexico / Q000453:epidemiology; D016017:Odds Ratio; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011401:Promoter Regions, Genetic; D018570:Risk Assessment; D012307:Risk Factors
chemical_list: C496541:HMOX1 protein, human; D051547:Heme Oxygenase-1