Unusual, interesting genetic disorders?

Ones you don't hear about too often, like osteogenesis imperfecta or Angelman's syndrome. Stuff resembling that.

Help is much appreciated!
Answers:
Marfan's Syndrome. This one affected the ancient pharaohs of Egypt and is still around today.
Celiac Disease. A very large incidence among the Irish. 1 within 200 people in that country have it .
usually Tourette's syndrome is quite mild...butVERY Severe Tourette's syndrome...paired with OCD, talking so doomed to failure the patient is knocking holes in the walls, hitting themselves within the head repeatedly, uncontrollably, requires restraining, can't walk, scream in agony, is breaking things, goes on rampages attacking others, scream in gibberish drooling and spitting, says they don't want to live anymore it's so bad... yeah, I'm the one who have it, that's my life and it isn't fun. I want the brain surgery but they say it's too risky but I want it to be over with, I'm set to kill myself but I can't do that but brain surgery could fix it so like I've got nil to lose.....plus the famed cursing...it's a miserable existence. Tourette's may be widely-known, but the existence I bear with it is certainly not the one relatives hear about.
Also...
Arterio-venous malformation. It's where blood vessel are formed wrong, tangled up in a little angioma, the fancy word for a tumor comprised of a kink of blood vessels. It's a genetic condition just as you request...my grandmother had one on her spine, a large-ish one that begin to press on her spinal cord and cut off neural activity, interfering with circulation and neurological function. She's paraplegic in a minute due to that. They can form anywhere on the spine or in the brain, knotted blood vessels and nerves, potentially homicidal if they form in the wrong place and cut off circulation or neural activity. Like, fearsome.
Fatal Familial Insomnia
mitochondrial disorder, leukodystrophy, spinal muscular atrophy

Related Questions:
Are here any experiments conducted to control heart rate?   Is nearby anyone that be frozen next to cryonics since disappearance?   Do doctors still prescribe barbiturates?   Tissue salt? Did you try it and did it remodel your robustness surrounded by any agency?   What is it beside adjectives these 'How much do surgeons craft!?  
  • What are the motions of the lumbar spine?What is the function of the erector spine?
  • Is Dentisty and Medicine different?
  • What are the different types of Doctors?