Werewolf syndrome - or hypertrichosis - results in excessive hair, save for the palms and the soles of the feet.
Rotting fish is not a pleasant smell, unless you're a cat.
If your 'startle response' is exaggerated, the last thing you want to be carrying is a chainsaw.
A South African albino boy stands next to his father.
SYDNEY: Healthy families are all alike; every unhealthy family is unhealthy in its own way. Sometimes it's because of a rare genetic disease. Rare genetic disorders often little studied, difficult to identify and take a long time to test possible treatments.
Sometimes, though, these diseases can give great insight into various functions of the human body. Cosmos takes a look at five rare inherited diseases.
FATAL FAMILIAL INSOMNIA
by Lisa Merolla
Starting in the 16th century, a wealthy Italian family was plagued with dementia and premature death. Curiously, the deaths seemed to be preceded by lengthy periods of sleeplessness. In 1986, studies of modern descendants of the family revealed a new genetic illness as the cause: fatal familial insomnia, or FFI.
Everyone has trouble sleeping occasionally, but FFI leaves the sufferers awake, night after night, increasingly disoriented. Gradually, other symptoms set in, including high blood pressure, impotence and short-term memory loss.
Even medication can't offer lasting relief. Sleeping pills stop working as the disorder progresses, says Joyce Schenkein, a neurophysiologist at Touro College in New York City, USA.
Average case lasts 18 months
Throughout this the sufferers retain the ability to think, and are frighteningly aware of your decline. As death approaches, you "experience dementia and eventually become mute and totally unresponsive," says Kelly Reynolds, a medical doctor and sleep scientist the Queensland Respiratory Laboratory in Brisbane.
The whole process takes between eight and 72 months, with an average case lasting 18 months.
Studying the living descendants of the Italian family with the disorder showed that FFI is caused by a mutation in tiny proteins called prions. Creutzfeldt-Jakob disease (CJD) - the human form of mad cow disease - is the most common prion disease; all of which lead to a damaging build-up of these proteins in the brain.
About 30 families
Since 1986, FFI has been found in 30 other families around the world. "In the past, the diagnosis had been missed," says Schenkein. "Now that the disease has been identified, they're finding it all over the world."
FFI symptoms typically arise at around the age of 50. There is currently no cure, but tests are underway on drugs to treat several forms of prion disease. The anti-malarial drug quinacrine, and several antibiotics have shown some promise.
In addition to finding a treatment, research into FFI is also giving insight into the mechanism and purpose of sleep.
Almost all of the damage caused by FFI occurs in the thalamus region of the brain, confirming the structure plays an important role in sleep. FFI also "gives a good sense of how important sleep is for cognitive function," Schenkein says.
NEXT: WEREWOLF SYNDROME
