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Health | Diseases & Conditions | Rare Diseases

Rare diseases may not be common, but they are no less painful or difficult than conditions you've heard of. Learn about the causes and symptoms of rare diseases as well as how patients can find treatments for their unusual conditions.

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What are the world's rarest diseases?

What if you were the only person in the world with a disease, and scientists used your name to classify it? How would doctors know what was wrong?


Alone We Are Rare, but Together We Are Strong: Orphan Diseases Quiz

Alone We Are Rare, but Together We Are Strong: Orphan Diseases Quiz

Orphan diseases are rare, but they are still serious conditions. Test your knowledge of orphan diseases with this quiz at HowStuffWorks. See more »

The Oldest Diseases of World Quiz

The Oldest Diseases of World Quiz

Take this HowStuffWorks quiz to learn all the horrible diseases you might've expired from in ancient times and the ones still around today! See more »

Frequently Asked Questions About Proteus Syndrome

Frequently Asked Questions About Proteus Syndrome

Proteus syndrome causes atypical development of bone and tissue, leading to physical deformities. See these frequently asked questions about Proteus syndrome. See more »

Frequently Asked Questions About Neurofibromatosis

Frequently Asked Questions About Neurofibromatosis

Neurofibromatosis is a genetic disorder that causes tumors to form on nerves throughout the body. Learn more about neurofibromatosis here. See more »

Top 10 Rare Diseases

Top 10 Rare Diseases

Rare diseases are usually genetic, but environmental factors can play a role. Take a look at the top 10 rare diseases that you may never have heard of. See more »

20 Diseases You've Probably Never Heard Of

20 Diseases You've Probably Never Heard Of

There are many diseases out there you've never heard of. We've put together the top 20 diseases you've probably never heard of that are rare and unusual. See more »

The Elephant Man Image Gallery

The Elephant Man Image Gallery

These pictures of the 'Elephant Man' are of one of the most shockingly disfigured person in history. See pictures of the 'Elephant Man' to learn more. See more »

Freak Show Quiz

Freak Show Quiz

They were peculiar, and sometimes horrifying, but what was really wrong with them? Test your knowledge of some famous circus freaks in this seven-question quiz. See more »

The Ultimate Diagnosis Quiz

The Ultimate Diagnosis Quiz

Think you know all there is to know about rare medical disorders? Play doctor and find out with this quiz! See more »

Fact or Fiction: Eradicated Diseases

Fact or Fiction: Eradicated Diseases

This eradicated disease quiz will test your knowledge of some of the diseases that science has defeated. Test yourself with this eradicated disease quiz. See more »