Takayasu arteritis and ulcerative colitis: A frequent association?

Previous studies have revealed that Takayasu arteritis (TAK) and ulcerative colitis (UC) sometimes develop in the same patients. However, the low prevalence of TAK has made it difficult to accumulate the number of cases to establish the ratio of co-occurrence. Recently, our Japanese group analyzed the data of 470 consecutive patients with TAK and revealed that 6.4 % of patients with TAK suffered from UC. This ratio is much higher than the prevalence of UC in Japan. HLAB* 52:01, the strongest susceptibility allele to both disease, showed strong enrichment in patients with these two diseases. IL12B, a common non-HLA susceptibility locus to both diseases, also showed a trend of enrichment. We also showed that other genetic determinants were shared between the two diseases. The high ratio of co-occurrence and genetic overlap suggest common molecular pathways centering on HLA-B*52:01 and IL12p40 underlying the two diseases.