Can sleep over 10+ hours daily
Have slept over 24 hours at least once a quarter to w/o need to urinate or eat.
Alarm clocks, people, even big dogs can't wake you.
Sleep drunkeness/inertia, Orthostatic hypotension, Raynaud's Phenomenon, and Syncope are common with the disorder.
No known biomarkers.
Separate from Narcolepsy type 1
Hypersomnia foundation.org is a good resource for this condition and other similar conditions.