Ankylosing spondylitis in West Africans - evidence for a non-HLA-B27 protective effect

Brown, M A, Jepson, A., Young, A., Whittle, H. C., Greenwood, B. M., & Wordsworth, B. P. (1997) Ankylosing spondylitis in West Africans - evidence for a non-HLA-B27 protective effect. Annals of the Rheumatic Diseases, 56(1), pp. 68-70.

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Objective -

To determine the prevalence of ankylosing spondylitis in the Fula ethnic group in The Gambia, and relate the disease prevalence to the B27 frequency and subtype distribution of that population.

Methods -

215 first degree relatives of 48 B27 positive Fula twin pairs, and 900 adult Fula males were screened for ankylosing spondylitis by clinical and, where appropriate, radiographic means. The B27 prevalence was determined by PCR/sequence specific oligonucleotides on finger prick samples from 100 unrelated Fula, and B27 subtype distribution by SSCP on unrelated B27 positive individuals. This data were then compared with the prevalence of ankylosing spondylitis among B27 positive Caucasians.

Results -

No case of ankylosing spondylitis was seen. Six per cent of Fula are B27 positive, of which 32% are B2703 and 68% B2705. Assuming the penetrance of ankylosing spondylitis in B27 positive Fula is the same as in B27 positive Caucasians, the probability of not observing any cases of ankylosing spondylitis among the Fula examined is remote (P = 6.7 x 10-6). Similarly, the chance of not seeing any cases among those expected to be either B2705 or B2703 was small (P = 3.2 x 10-4 for B2705, and P = 0.02 for B2703).

Conclusions -

The risk of developing ankylosing spondylitis in B27 positive Fula is lower than in B27 positive Caucasians. This is not explained by the B27 subtype distribution among Fula, and suggests the presence of some non-B27 protective factor reducing the prevalence of ankylosing spondylitis in this population.

Impact and interest:

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ID Code: 87728
Item Type: Journal Article
Refereed: Yes
Additional Information: No file attached.
Keywords: HLA B27 antigen, adult, ankylosing spondylitis, article, controlled study, female, gambia, HLA typing, human, major clinical study, male, prevalence, priority journal, twins, Disease Susceptibility, Ethnic Groups, HLA-B27 Antigen, Humans, Middle Aged, Polymerase Chain Reaction, Spondylitis, Ankylosing
DOI: 10.1136/ard.56.1.68
ISSN: 0003-4967
Divisions: Current > Schools > School of Biomedical Sciences
Current > Institutes > Institute of Health and Biomedical Innovation
Deposited On: 25 Sep 2015 01:29
Last Modified: 25 Sep 2015 01:29

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