title: Familial aggregation of ankylosing spondylitis in Southern China.
abstract: OBJECTIVE
  To study the familial aggregation of ankylosing spondylitis (AS) in southern China and to compare the clinical and laboratory characteristics between the probands and their first-degree relatives with AS.
  
  
  METHODS
  On the basis of questionnaires to 473 patients with AS, 402 responded and 36 self-reported having first-degree relatives with symptoms related to spondyloarthropathies. All together, 144 of 150 first-degree relatives of these 36 probands were examined for clinical and radiographic characteristics. HLA typing for HLA-B27 was performed by standard microlymphocytotoxicity method.
  
  
  RESULTS
  The disease duration of the 36 probands was 5.03 +/- 3.76 years (0.5-14 yrs). Forty seven first-degree relatives of the 36 probands were diagnosed as having AS. The prevalence of AS among the first-degree relatives of these 36 aggregated families was 31.3%. The overall prevalence of AS among the first-degree relatives in these 402 families was estimated to be 2.8%. The recurrence risk of the first-degree relatives within these aggregated families was 31.3%, suggesting an excess risk to them of 120.4, while it was 10.8 to the general families. The probands more often had peripheral arthritis and enthesopathies (p < 0.001 and p = 0.01, respectively) than the AS patients among the first-degree relatives. HLA-B27 was associated with development of AS in the probands and the patients among the first-degree relatives.
  
  
  CONCLUSIONS
  Although familial aggregation of AS in southern China is uncommon in general, the recurrence risk of the first-degree relatives of AS probands within the aggregated families is extremely high, according to our study among hospital based patients. As the disease of the first-degree relatives is often mild and atypical, familial background analysis should be encouraged to assist early diagnosis.
authors: National Public Health Institute, Turku, Finland. yiliu@utu.fi
authors: Y
authors: Y
authors: Liu
authors: J
authors: J
authors: Li
authors: B
authors: B
authors: Chen
authors: H
authors: H
authors: Helenius
authors: K
authors: K
authors: Granfors
mesh_terms: D000293:Adolescent; D000328:Adult; D002681:China / Q000453:epidemiology; D005192:Family Health; D020022:Genetic Predisposition to Disease; D015796:HLA-B27 Antigen / Q000235:genetics; D006801:Humans; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D013167:Spondylitis, Ankylosing / Q000208:ethnology* / Q000235:genetics
chemical_list: D015796:HLA-B27 Antigen