1. HLA-B51
The HLA-B51 gene is used in the diagnosis of Behçet's disease, an inflammatory condition affecting the blood vessels of the mouth, genitals, skin, and eyes. This disease most commonly occurs in individuals aged 30 to 40. In about 75% of patients, ulcers are observed in both the mouth and genital areas. More than 50% of patients develop inflammatory lesions in the eyes, which can lead to vision problems and, if left untreated, may result in blindness. In rare cases, the disease may involve the brain, gastrointestinal tract, or central nervous system.
Complications in the CNS can manifest as headaches, personality changes, speech difficulties, memory loss, and coordination problems. Gastrointestinal involvement may lead to ulcers in the intestinal wall and serious infections. These complications tend to worsen with age.
HLA testing is a blood test used to determine a person’s genetic immune profile.
2. HLA-B27
The HLA-B27 gene is associated with increased susceptibility to certain autoimmune diseases. It is primarily used in the diagnosis of Ankylosing Spondylitis (AS), a chronic inflammatory disease of the spine and sacroiliac joints. It initially affects the spine, and over time, the affected vertebrae may begin to fuse, resulting in complete loss of spinal flexibility.
As the disease progresses, it may impair chest expansion and deep breathing. Around 40% of patients experience eye inflammation, which can cause eye pain and photophobia (increased sensitivity to light). HLA testing is also useful for assessing the risk of organ transplant rejection and diagnosing autoimmune diseases.
3. HLA-DRB1
The HLA-DRB1 gene is used in the diagnosis of Rheumatoid Arthritis (RA), a chronic autoimmune disease characterized by joint inflammation. RA can lead to progressive joint damage, resulting in limited mobility. The inflammation typically appears symmetrically—if it occurs in one hand, it likely affects the other as well. Over time, patients may experience weight loss and decreased energy.