HLA-B27 tag — ankylosing spondylitis risk
A tag SNP for the HLA-B27 allele has been detected (one copy).
You carry one copy of the immune system version linked to a specific kind of inflammatory back arthritis.
Carriers of HLA-B27 have substantially elevated lifetime risk of ankylosing spondylitis and related spondyloarthritis, but most carriers (~95%) never develop these conditions.
Your lifetime risk of developing this kind of arthritis is several times higher than average, but about 95 in 100 people with this version never get it.