MrSnoopy went to school with a girl who had some really rare lung disease. Her mother had it too, and both of them died from it. They were two of only like, 42 cases worldwide.
So what’s the rarest disease in the world, anyway? Has there ever been a person to be the only one in the world with something?
I remember seeing a case on TV of a couple whose daughter was still mentally and physically the equivilent of a baby despite being about nine years old. She couldn’t talk, walk, or dress herself, and had to be bottle-fed. The doctors were completely stumped and there was no mention made of any case quite like it.
Geez. Any idea where I could read about this?
Here’s a nice one: [Fatal Familial Insomnia](http://Fatal Familial Insomnia). IIRC, there is an inherited variant that only exists in one bloodline from Italy. Google around…it’s a pretty horrible disease.
Jon
There’s plenty of diseases described in one patient or a proband. They are not usually named, except as variants of other diseases. The real problem is that usually one case is not enough for publishing, unless it is truly bizarre (like Nichol_storm’s thing). One case is usually not enough to adequately describe a disease. If something is not published, then there is no scientific record of it ever happening.
Another issue is with your definition of a disease. There is a wide spectrum of things that can cause disorders in the body, from single genes to multiple genes to environment. Environment can make truly bizarre phenotypes on its own, ranging from developmental disturbance to odd symptoms in an adult. These may not meet your criteria for disease, even though some are pretty weird. Like Phineas Gage (who had the front of his brain blown out by a tamping rod and lived for years with no cerebral cortex). There are other more ambiguous examples – rare toxicity syndromes and the like (ALS/Parkinsonism of Guam to name a more common one). With genetics, it is even worse. For nearly every genetic disease, there are rare variants reported: late onset Tay-Sachs, autosomal recessive osteogenesis imperfecta, etc. etc. with only one to a few cases reported.
Even relatively common diseases present with strangely. A famous example is Stephen Hawking. We were told that he was diagnosed as having amyotrophic lateral sclerosis or Lou Gehrig’s disease. Pretty much all patients who receive this diagnosis die within 5 years. He has been alive for 30. He may have been misdiagnosed (for instance, it could be SMA4 with a weird upper/lower motor neuron presentation), or he could just be odd.
You may also get a weird case when multiple diseases or abnormalities are reported in one individual. This can be because of a rare or new deletion of DNA, chromosomal rearrangements or loss, or many other factors. Since I was just reading about genomic imprinting for another GQ thread, I read a 1988 report of one girl with cystic fibrosis, mental retardation, and short stature. These were due to the fact that she inherited both of her chromosome 7s from her mother (maternal isodisomy). Since there is different gene expression from the mother and the father, it caused problems. This would mean that she is probably the result of 2 nondisjunctions: the sperm lacked a 7 and the egg had two. Needless to say, this is incredibly rare.
I agree with edwino, the rarest disease in the world is probably something so rare it has never even been described.
Keep in mind large chunks of the world’s population don’t have access to cutting edge medical care. My company deals with rare diseases (in the range of a few thousand patients in the US and another few thousand in Europe). Occasionally the question comes up how many such cases exist in, say, Africa, or Asia? We can only guess because many countries don’t have the medical infrastructure we take for granted in the US or Western Europe.
The rarest diseases probably happen to only one person. These will probably be misdiagnosed by doctors/coroners/medical examiners, and we’ll never know about them.
Think of this as natural selection at work. And you thought we humans were immune…
Joseph Merrick, the “Elephant Man,” might have suffered from something called “Proteus Syndrome.” It was only described in the past 30 years, and fewer than 100 people have been identified.
There hasn’t been a single case of Smallpox in over twenty years. That puts it right at the top of any comprehensive list of rare diseases.
[Dr. Hibert]
Well Homer, it seems you have an extremely rare condition known as “Homer Simpson’s Disease”!
[/Dr. Hibert]
I have an orthopedic condition that occurs on something of the order of one in a million people. I’m sure there are rarer conditions out there, but I think I’m well up there.
I didn’t know about anybody else with it until the internet came along.
Well, there’s Fibrodysplasia Ossificans Progressiva, the disease that slowly turns your connective tissue into bone.
About 2,500 people suffer from it, worldwide. I think it counts as “pretty rare.”
And there’s always www.rarediseases.org/search/rdblist.html
You’re welcome. Pleasant dreams.
Jake4, I was thinking the same thing. If it happens to maybe a half dozen people worldwide, it’s almost impossible to diagnose and confirm. Remember, if it happens in a jungle without credible witnesses, it didn’t happen.
Rarity would mean an established disease, right? Smallpox springs to mind, but I won’t try to spend much time speculating, since I’m sure others will have oddball sites they can cite.
My best offerring (unnamed as yet) would be the virus that puts a rational thought in any French PM’s head. This is a long shot, though
A relative on my wifes side has Degos Syndrome which has been identified in 150 cases worldwide. They are having a great deal of difficulty finding any sort of therapy/research being done because it is so rare.
How about Kuru, or laughing sickness? It affects only New Guinean cannibals and is thought to be the result of prion infection form eating human brains.
That’s gotta be pretty rare. Hopefully, anyway.
Common sense. 
At first, I thought this post was a joke based on the book Freak Show, the only other place I’d ever heard the term. A man explains that he has multiple neurofibromatosis. Oz, tells him that what he actually has is Proteus Syndrome. Until I saw your post, and did a search on the term, I assumed PS was an invention of the author.
Sadly, the Amazon listing does not contain an excerpt from the book. Freak Show neither laughs at and exploits those born different, nor preaches about prejudice or judging people by their appearance. It’s a marvellous book and I highly recommend it.
I was going to say Tom Jones Disease, but then I realised it’s not unusual.
Her symptoms seem to be rather more common than we may wish. There are many people out there who never learn those skills due to mental retardation or brain damage. By physically an infant, do you mean that she not grown past the size of a infant?
I know a family who are the only known case of hereditary tumors on the heart. The tumors are cancerous in one gender (I forget whether the cancer occurs in women or men) and benign but deadly in the other. This has been traced back five generations. Today, three members of this bloodline are alive. One is the first member of this family to live past 50, thanks to open-heart surgery. One is living with a heart transplant, and one has tumors that are monitered but haven’t grown to a dangerous size yet.
Perhaps a Doper with access to medical journals could look them up?
For some reason there is a special spot in my brain devoted to strange things. It is just aft of the larger section that contains useless trivia. But within this special spot is a smaller location that records strange diseases.
There is the disease of people who are allergic to sunlight. Yes, allergic. They break out in hives and have trouble breathing. It is strictly heriditary, and skips generations. There are two young daughters of an American couple that would have to take them outside to play between the hours of midnight and 4 am. Only about a hundred cases are known.
There is also the strange bread fungus disease that kills within hours. There have only been about a dozen cases known. One of the survivors is an American whose doctors caught it just in time, coincidentally, because one of them had just read about it a week earlier. They had to remove his eyes, nose, and upper portion of his mouth in order to save his life. He still lives somewhere in Texas, IIRC.