Familial aggregation of ankylosing spondylitis in Southern China.
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.
Liu
Y
Y
National Public Health Institute, Turku, Finland. yiliu@utu.fi
Li
J
J
Chen
B
B
Helenius
H
H
Granfors
K
K
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
D015796:HLA-B27 Antigen