M. Khan
Published: 1st July 1995
Abstract:
“Twenty-five years ago, HLA-B27 was recognized as a new HLA specificity.
It is present throughout Eurasia but is virtually absent among the genetically unmixed native populations of South America, the Bantus and Sans (Bushmen) of equatorial and southern Africa, and the aborigines of Australia.
B27 is a serologically determined specificity that encompasses nine different allotypes (subtypes), B*2701 to B*2709.
Ankylosing spondylitis or related spondyloarthropathies thus far have been documented in individuals with any of the following five subtypes: B*2701, B*2702, B*2704, B*2705, or B*2707”
Key Findings:
Please note: I do not have access to the full paper, however the authors of the following paper: ‘Prevalence of HLA-B27 in the New Zealand Population: Effect of Age and Ethnicity’ provide an excellent summary of some of the key findings.
What follows are their words:
They note that:
“The association of HLAB-27 within the broader group of spondyloarthropathies (SpA) varies significantly, ranging from <50% in psoriatic, enteropathic, and inflammatory bowel disease-associated SpA, to 80% in reactive arthritis, to >95% in AS.
The frequency of the HLA-B27 allele also varies widely across populations. Both a north–south gradient and an east–west gradient have been observed for HLA-B27 prevalence in the Northern Hemisphere.
It is hypothesised that these gradients result from the negative selection pressure exerted by malaria.
In regions where malaria is endemic, the prevalence of HLAB-27 is low, and vice versa.
HLA-B27 is highly prevalent in Northern Eurasia and North America, with 10 to 16% of Norwegians, Swedes and Icelanders and 25 to 50% of Inuit, Yupik and Indigenous Northern Americans (for example, Haida and Bella Coola) carrying this allele.
HLA-B27 prevalence decreases to 9.5% in the United Kingdom, and further decreases to 2 to 6% in Mediterranean regions.
In a similar manner, HLA-B27 prevalence decreases from west to east.
In Southeast Asia prevalence of HLA-B27 can exceed 12%, but in mainland China the range is between 2 and 6%. HLA-B27 prevalence also varies significantly within the Pacific Islands. In Melanesia the prevalence is high, whereas HLA-B27 is uncommon in Micronesia and absent in unmixed native populations of Southeast Polynesia.”
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