HLA-B*51 allelic and carrier frequency in Kazakhstan: insights into Behçet's disease prevalence in Central Asia.

Behçet's disease (BD) is a systemic vasculitis whose prevalence varies according to the ethnicity. HLA-B51 is a well-known genetic factor predisposing to BD: populations with higher HLA-B51 allelic frequencies are also those with a greater disease prevalence, as occurs in the Silk Road countries. However, the BD prevalence is unknown in many countries, including Kazakhstan and, in general, Central Asia, despite the location on or near the Silk Road. Due to the lack of clinical studies from this area, we analyzed the bone marrow donors registry in Kazakhstan, in order to assess the HLA-B*51 allelic and carrier frequencies, which resulted to be 8.14 and 15.28%, respectively. Through a comparison with the same parameters in other countries (by performing a data search in the medical literature and in the Allele Frequency Net Database), we might speculate a BD prevalence in Kazakhstan of 10-15/100.000 at least. This result should prompt a greater clinical consideration of this disease in Central Asia, as well as the publication of clinical data from this geographic area.