title: Patients with psoriatic arthritis may show differences in their clinical and genetic profiles depending on their age at psoriasis onset.
abstract: OBJECTIVE
  The age of psoriasis onset has an important impact on the clinical expression and heritability of psoriasis. Psoriasis characteristics according to the age at disease onset have been extensively studied. However, the impact of the age of psoriasis onset on psoriatic arthritis (PsA) features has not been analysed in depth. The aim of the present paper is to analyse whether the age of psoriasis onset may have an impact on the clinical and genetic characteristics in a cohort of PsA patients.
  
  
  METHODS
  The study included 110 PsA patients classified in accordance with the CASPAR criteria. Patients were divided into early (onset age <30 years) and late (onset age >30 years) onset psoriasis, and clinical features were studied in accordance to this stratification. Distribution of several genes within the MHC region were analysed in accordance with the prior stratification, and their frequencies compared to that of 110 healthy matched blood donors.
  
  
  RESULTS
  Compared to patients with late-onset disease, PsA patients with early-onset psoriasis showed more frequently: a longer psoriasis-arthritis latency period (9.9±6 years vs. 3.8±4 years, p=0.0001), a positive family history of disease (60.3% vs. 20.5%, OR 6.1, 95% CI: 2.5-15.0, p=0.0001), severe psoriasis (PASI 8.2±4 vs. 3.6±2.2, p=0.0001), clinical enthesitis (37.7% vs. 22.4%, OR 2.09, 95% CI: 0.9-4.9, p=0.08), and oligoarthritis (47.5% vs. 28.6%, OR 2.26, 95% CI: 1.02-5.02, p=0.04). MICA-A9 was associated with susceptibility in both early-onset (60.7% vs. 30%, p=0.0002) and late-onset patients (59.2% vs. 30%, p=0.0008). However, HLA-Cw*0602 was significantly increased in patients with early-onset psoriasis (73.8% vs. 17%, p<0.0001), whereas the allele 384 of the microsatellite C1_4_4, located 34 kb telomeric to HLA-C locus, was increased only in late-onset cases (49% vs. 21%, p=0.001).
  
  
  CONCLUSIONS
  Clinical and genetic features of PsA may differ depending on the age at psoriasis onset. This type of stratification should be considered in future genetic and epidemiological studies of PsA.
authors.affiliation: Hospital Universitario Central de Asturias, Oviedo, Spain. ruquei@mixmail.com
authors.forename: Rubén
authors.initials: R
authors.lastname: Queiro
authors.forename: Mercedes
authors.initials: M
authors.lastname: Alperi
authors.forename: Sara
authors.initials: S
authors.lastname: Alonso-Castro
authors.forename: Javier
authors.initials: J
authors.lastname: Ballina
authors.forename: Leticia
authors.initials: L
authors.lastname: Huergo-Zapico
authors.forename: Azahara
authors.initials: A
authors.lastname: Fernández-Guizán
authors.forename: Andrea
authors.initials: A
authors.lastname: Acebes-Huerta
authors.forename: Jesús
authors.initials: J
authors.lastname: Martínez-Borra
authors.forename: Cristina
authors.initials: C
authors.lastname: Sarasqueta
authors.forename: Carlos
authors.initials: C
authors.lastname: López-Larrea
authors.forename: Segundo
authors.initials: S
authors.lastname: González
mesh_terms: D000328:Adult; D017677:Age Distribution; D017668:Age of Onset; D015535:Arthritis, Psoriatic / Q000453:epidemiology* / Q000235:genetics* / Q000276:immunology; D015331:Cohort Studies; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics; D006023:Glycoproteins / Q000235:genetics / Q000276:immunology; D015236:HLA-C Antigens / Q000235:genetics* / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000276:immunology; D006650:Histocompatibility Testing; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D008875:Middle Aged; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000276:immunology; D011110:Polymorphism, Genetic / Q000235:genetics / Q000276:immunology; D012307:Risk Factors; D016615:Telomere / Q000235:genetics
chemical_list: C109656:CDSN protein, human; D006023:Glycoproteins; D015236:HLA-C Antigens; C491620:HLA-C*06:02 antigen; D015395:Histocompatibility Antigens Class I; D036341:Intercellular Signaling Peptides and Proteins; C099187:MHC class I-related chain A; D050814:Octamer Transcription Factor-3; C494173:POU5F1 protein, human