Glossary

human leukocyte antigen [HLA]

The human leukocyte antigen (HLA) system is the group of genes (a section or part of your DNA that has instructions for making things your body needs to work) that instruct proteins on the surface of white blood cells. These proteins help control your immune system and your ability to fight infection.

HLA typing is a test that identifies your human leukocyte antigens. Doctors may also order HLA typing to help diagnose narcolepsy type 1 (NT1). Most people with NT1 have the HLA-DQB1*0602 gene and are referred to as being “HLA-DQB1*0602 positive.”