title: mtDNA haplogroups and osteoarthritis in different geographic populations.
abstract: OBJECTIVE
  To compare the frequency distribution of the mtDNA haplogroups in OA patients and healthy controls between the United Kingdom (UK) and Spain.
  
  
  METHODS
  We used the single base extension (SBE) assay to obtain the European mtDNA haplogroups in 1471 OA patients and 406 healthy controls from Spain, and 453 OA patients and 280 healthy controls from the UK. Some differential haplogroup J-related single nucleotide polymorphisms (SNPs) between both populations were analyzed. The whole data was analyzed with SPSS software (v.18) following appropriate approaches that included chi-square contingency tables and logistic regression models adjusting by gender and age.
  
  
  RESULTS
  The haplogroup J appeared underrepresented in OA patients from Spain when compared with healthy controls (OR=0.636; 95% CI: 0.444-0.911; p=0.013). Individuals from the UK carrying the haplogroup T showed a decreased risk of OA (OR=0.574; 95% CI: 0.350-0.939; p=0.027). The comparison of the frequency distribution of the haplogroup J between the UK and Spain showed a decreased presence of this haplogroup in healthy controls from the UK when compared with healthy controls from Spain that is in borderline of the statistical significance (p=0.06). The analysis of some haplogroup J-related SNPs in OA patients and healthy controls from Spain and the UK showed that the SNP m.3394t>c appeared underrepresented in the UK cohort (p=0.038).
  
  
  CONCLUSIONS
  The proposed mitochondrial uncoupling mechanism derived from the mtDNA haplogroups J and T could be behind their protective role against OA. The different association found in Spain and the UK could reflect the adaptation of the mtDNA haplogroups to different climatic patterns. The genetic composition of the haplogroup J between the UK and Spain seems to be slightly different, being the m.3394t>c SNP one of the differentially expressed haplogroup J-related polymorphisms.
authors.affiliation: Grupo de Genómica. Servicio de Reumatología. Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas. Universidade da Coruña (UDC). As Xubias, 15006. A Coruña, España; RETIC-RIER, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Soto-Hermida
authors.affiliation: Grupo de Genómica. Servicio de Reumatología. Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas. Universidade da Coruña (UDC). As Xubias, 15006. A Coruña, España; RETIC-RIER, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Fernández-Moreno
authors.affiliation: Grupo de Genómica. Servicio de Reumatología. Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas. Universidade da Coruña (UDC). As Xubias, 15006. A Coruña, España; RETIC-RIER, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Oreiro
authors.affiliation: Grupo de Genómica. Servicio de Reumatología. Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas. Universidade da Coruña (UDC). As Xubias, 15006. A Coruña, España; RETIC-RIER, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Fernández-López
authors.affiliation: Grupo de Genómica. Servicio de Reumatología. Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas. Universidade da Coruña (UDC). As Xubias, 15006. A Coruña, España; RETIC-RIER, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Rego-Pérez
authors.affiliation: Grupo de Genómica. Servicio de Reumatología. Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas. Universidade da Coruña (UDC). As Xubias, 15006. A Coruña, España; CIBER-BBN, Instituto de Salud Carlos III, Madrid, Spain; RETIC-RIER, Instituto de Salud Carlos III, Madrid, Spain. Electronic address: francisco.blanco.garcia@sergas.es.
authors.forename: F J
authors.initials: FJ
authors.lastname: Blanco
mesh_terms: D004272:DNA, Mitochondrial / Q000235:genetics*; D005787:Gene Frequency; D006239:Haplotypes; D006801:Humans; D010003:Osteoarthritis / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D013030:Spain; D006113:United Kingdom
chemical_list: D004272:DNA, Mitochondrial
keywords: Mitochondria; Osteoarthritis; Uncoupling; mtDNA haplogroups; mtDNA sequence