Bw51 was associated with Behçet's disease,[5] in endemic (versus epidemic) mucocutaneous lymph node syndrome,[6] susceptibility to the virus that causes German measles infection.
[7] Behçet's disease is an inflammation of the wall of blood vessels that can involve the eyes, skin, and the rest of the body.
[8] Several alleles of B51 (B*5101, B*5108, B*5105, and B*5104) are found in disease, and linkage to markers, D6S285, in the HLA locus was strong (P<0.005).
[9] Homozygotes of B51 showed considerably high risk for disease indicating a possible gene-dose effect.
[15] However, B51 tends not to be found in ABD when a certain SUMO4 gene variant is involved,[16] and symptoms appear to be milder when HLA-B27 is present.