Narcolepsy, Idiopathic Hypersomnia, Kleine Levin syndrome, and Non-24-Hour Sleep-Wake Disorder are all recognised rare diseases.

For more information about these sleep disorders:
Narcolepsy
Idiopathic Hypersomnia
Kleine Levin syndrome
Non-24-Hour Sleep-Wake Disorder

You can also check out the Genetic and Rare Disease (GARD) Information Center or Orphanet

Rare Disease Day is held on the last day of February every year to raise awareness of rare diseases.
http://www.rarediseaseday.org/

28 February 2019

The theme for Rare Disease Day 2019 is 'Bridging health and social care'. Focusing on bridging the gaps in the coordination between medical, social and support services in order to tackle the challenges that people living with a rare disease and their families around the world face every day.

Rare Disease Day 2019 is an opportunity to be part of a global call on policy makers, healthcare professionals, and care services to better coordinate all aspects of care for people living with a rare disease. Read more

28 February 2018 marked the tenth international Rare Disease Day coordinated by EURORDIS. On and around this day hundreds of patient organisations from countries and regions all over the world held awareness-raising activities based on the theme of research.

Rare Disease Day 2018 was an opportunity to call upon researchers, universities, students, companies, policy makers and clinicians to do more research and to make them aware of the importance of research for the rare disease community.
Read more about the 2018 campaign

“With research, possibilities are limitless” - Rare Disease Day

"Rare diseases are rare, but rare disease patients are numerous" - Orphanet