HLA & immunogenetics

Narcolepsy

HLA-DQB1*06:02

Narcolepsy type 1 is characterised by excessive daytime sleepiness and often cataplexy, and is usually associated with low hypocretin. HLA-DQB1*06:02 is strongly associated with the condition but is also found in many people without narcolepsy. Frequencies vary across populations.

Key points

  • The variant is very common in case studies, but is also widespread in the general population.
  • Finding it alone does not confirm narcolepsy.
  • HLA typing does not replace sleep studies or clinical assessment.

A very tight but unspecific link

HLA-DQB1*06:02 is a strong association marker for narcolepsy type 1, but it is not a diagnostic test. Because the variant is also common in people without the condition, finding it does not show whether someone has narcolepsy. The meaning of a negative result also depends on clinical context and the population studied.

Context

The diagnosis rests on clinical findings, sleep laboratory and, where appropriate, the hypocretin level in cerebrospinal fluid. Genome shows only the HLA type as technical evidence, without diagnostic claim.

What Genome measures. Whether HLA-DQB1*06:02 is present in the HLA typing. The marker does not replace sleep testing and is neither proof nor a reliable exclusion on its own.

Related topics

HLA and autoimmunityHLA typing

Sources

  1. 1Tafti et al., 2014 DQB1 locus alone explains most of the risk and protection in narcolepsy with cataplexy in Europe. Sleep 37:19-25. doi.org/10.5665/sleep.3300
  2. 2Liblau et al., 2015 Hypocretin (orexin) biology and the pathophysiology of narcolepsy with cataplexy. The Lancet Neurology 14:318-328. doi.org/10.1016/S1474-4422(14)70218-2