Which disease is strongly associated with a HLA Class I allele?

Ankylosing spondylitis is strongly associated with the HLA-B27 allele, which is a specific type of HLA Class I allele. The association between HLA-B27 and ankylosing spondylitis is well-documented, indicating that individuals expressing this allele have a significantly higher risk of developing the disease. The pathophysiology of ankylosing spondylitis involves immune-mediated processes where the presence of HLA-B27 is thought to trigger an inappropriate immune response, leading to inflammation and progressive fusion of the spine and other joints.

In contrast, Type I insulin-dependent diabetes mellitus and multiple sclerosis are primarily associated with HLA Class II alleles, such as HLA-DR. Narcolepsy has also been linked to HLA Class II, particularly with the DQB1*06:02 allele. Thus, while these other diseases have genetic associations, they do not link directly to HLA Class I alleles in the same definitive way as ankylosing spondylitis does with HLA-B27.