Twenty years after the colony was established at Stanford University, linkage analysis identified the causative allele on
the hypocretin receptor 2 (hcrtr2) gene [86].
A genetic basis has been found in Labrador Retrievers and Doberman Pinschers and is due to a mutation involving
the hypocretin receptor 2.
Mignot and his colleagues have begun population studies to see whether
hypocretin receptor 2 mutations appear in narcoleptic people.
First identified in humans early last year,
hypocretin receptor 2 was tentatively linked by other researchers to metabolism.
Hypocretin — which binds to
hypocretin receptor 2 — is manufactured in large quantities in some parts of the hypothalamus, an area known to be important in regulating sleep.
Using gene mapping techniques, the researchers zeroed in on a mutation in the gene for
hypocretin receptor 2.
The hypocretin receptor 2 gene could be the single most important gene in human narcolepsy, says Michael Aldrich, a neurologist and director of the University of Michigan's Sleep Disorders Center.
Relying on tests that used blood from Pandemrix recipients, the study authors showed it triggered antibodies that not only attack the virus but also bind to
hypocretin receptors, potentially killing them.
Not exact matches
The
receptor is present but the
hypocretin isn't.
Think of brain cells as rooms with locks called
receptors on their surfaces and a
hypocretin as a key that is also a stimulant.
Their search turned up a suspect: a piece of a
receptor for
hypocretin resembles part of the H1N1 influenza nucleoprotein — which binds to the virus genome and plays a key role in its replication.
Mignot and his colleagues identified a spontaneous genetic mutation in those animals that incapacitated a
receptor in brain cells for
hypocretin.
Hypocretin Neurons express leptin
receptors.