title: ANKH and susceptibility to and severity of ankylosing spondylitis.
abstract: OBJECTIVE
  Unconfirmed reports describe association of ankylosing spondylitis (AS) with several candidate genes including ANKH. Cellular export of inorganic pyrophosphate is regulated by the ANK protein, and mutant mice (ank/ank), which have a premature stop codon in the 3' end of the ank gene, develop severe ankylosis. We tested the association between single-nucleotide polymorphisms (SNP) in these genes and susceptibility to AS in a population of patients with AS. We investigated the role of these genes in terms of functional (BASFI) and metrological (BASMI) measures, and the association with radiological severity (mSASSS).
  
  
  METHODS
  Our study was conducted on 355 patients with AS and 95 ethnically matched healthy controls. AS was defined according to the modified New York criteria. Four SNP in ANKH (rs27356, rs26307, rs25957, and rs28006) were genotyped. Association analysis was performed using Cochrane-Armitage and linear regression tests for dichotomous and quantitative variables. Analyses of Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), BASFI, and mSASSS were controlled for sex and disease duration.
  
  
  RESULTS
  None of the 4 markers showed significant single-locus disease associations (p > 0.05), suggesting that ANKH was not a major determinant of AS susceptibility in our population. No association was observed between these SNP and age at symptom onset, BASDAI, BASFI, BASMI, or mSASSS.
  
  
  CONCLUSIONS
  These results confirm data in white Europeans that ANKH is probably not a major determinant of susceptibility to AS. ANKH polymorphisms do not markedly influence AS disease severity, as measured by BASMI and mSASSS.
authors.affiliation: Faculdade de Ciências Médicas, Universidade Nova de Lisboa, CEDOC, Campo Mártires da Pátria 130, Lisbon 1169-056, Portugal. pimentel.santos@gmail.com
authors.forename: Fernando Manuel
authors.initials: FM
authors.lastname: Pimentel-Santos
authors.forename: Dario
authors.initials: D
authors.lastname: Ligeiro
authors.forename: Mafalda
authors.initials: M
authors.lastname: Matos
authors.forename: Ana Filipa
authors.initials: AF
authors.lastname: Mourão
authors.forename: Elsa
authors.initials: E
authors.lastname: Vieira de Sousa
authors.forename: Patricia
authors.initials: P
authors.lastname: Pinto
authors.forename: Ana
authors.initials: A
authors.lastname: Ribeiro
authors.forename: Helena
authors.initials: H
authors.lastname: Santos
authors.forename: Anabela
authors.initials: A
authors.lastname: Barcelos
authors.forename: Fatima
authors.initials: F
authors.lastname: Godinho
authors.forename: Margarida
authors.initials: M
authors.lastname: Cruz
authors.forename: Joao Eurico
authors.initials: JE
authors.lastname: Fonseca
authors.forename: Henrique
authors.initials: H
authors.lastname: Guedes-Pinto
authors.forename: Helder
authors.initials: H
authors.lastname: Trindade
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Brown
authors.forename: Jaime C
authors.initials: JC
authors.lastname: Branco
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D004198:Disease Susceptibility; D005260:Female; D005819:Genetic Markers; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D028061:Phosphate Transport Proteins / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D013167:Spondylitis, Ankylosing / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology*; D044465:White People / Q000235:genetics; D055815:Young Adult
chemical_list: C498770:ANKH protein, human; D005819:Genetic Markers; D028061:Phosphate Transport Proteins