Why we built this, and what we promise

There are no rare diseases — only diagnoses that come late — or come wrong.

Most conditions called “rare” are not so much uncommon as uncommonly recognized. The signs are usually there for years, often in tests someone already ran. Each result was read on the day it came back, against a range built from other people. Laid side by side, the same results can tell a different story. The disease was rarely the rare part; the diagnosis was. And that is the hopeful part: a diagnosis that came late, or came wrong, can still be found — which is what this is here to help you do. Your own doctor — your PCP — knows you over time and has a long-term stake in you, which makes them the one placed to see all of you; this is here to help you work with them.

A calm, plain-language walk through what is happening to you — the genuinely rare conditions, and the common ones that get missed. It is written for patients and the people beside them, and just as much for the clinician working against the clock — anyone trying to understand, and to share their thoughts, is welcome. The interactive pages here will even help you put those thoughts together. New: an early-warning approach. The blood and urine tests you already have often carry signals years before anyone names the problem. We are building checks that help you and your doctor read them, starting with the most common brush-off: “it’s probably just dehydration.” No jargon, no accounts, and nothing you read or type is sent anywhere. Take whatever time you need.

Reading is private. No accounts, and nothing you read or type on these pages is sent anywhere.

How long the wait really is

Half are found within a year. A quarter wait five years or more.

In a large European survey of people with a rare disease, about half had their diagnosis within a year of their first symptoms. About one in four waited five years or more. Strong evidence (Faye et al., Eur J Hum Genet 2024)

An average is pulled by the longest waits, the way one very tall person raises a room's average height. A few people waiting ten or twenty years lift the average to 4.7 years, while the middle person (the median, the one in the middle of the line) waited about 9 months. Both numbers are true. The median tells you what is typical; the average tells you how long the long waits are. Strong evidence

Most of the time passed after the first appointment, not before it: on average about five months from first symptom to first visit, then a little over four years from first visit to a confirmed diagnosis. Strong evidence

People who were referred to a centre of expertise (a clinic that sees many people with one group of rare conditions) waited on average about 4 years, against about 5 years for people who were not. After the authors allowed for other differences between the groups, the link was smaller but still pointed the same way. Good evidence

Longer waits were linked with symptoms that began in childhood or adolescence, being a woman, seeing many different clinicians, and having been given a wrong diagnosis first. Strong evidence

Faye F, Crocione C, Anido de Peña R, et al. Time to diagnosis and determinants of diagnostic delays of people living with a rare disease: results of a Rare Barometer retrospective patient survey. Eur J Hum Genet 2024;32:1116–1126. doi:10.1038/s41431-024-01604-z. 6,507 people, 1,675 rare diseases, 41 countries, surveyed online in 2022 by EURORDIS.

What keeps this honest: people answered from memory; only people who already had a diagnosis could answer, so those still waiting are missing and the true wait is probably longer; and the centre-of-expertise link is an association, not proof that referral shortens the wait.

What we promise, and you can check

Free, no accounts. Nothing you read or type here is kept unless you choose to share it, and we ask each time.
Every claim shows its evidence. Numbers carry a grade and a source. Where our own methods are still being tested, we say so.
As deep as you want. Each section is complete in plain words; open a line beneath it for the reasons, then the numbers, then the caveats.
Early warnings from tests you already have. Checks that help you and your doctor read what is already in your results, starting here.
Hints, never verdicts. We help you ask a sharper question. Your doctor makes the call.

A spoken conversation that answers only from this library, shows the source of every answer, and says plainly when we don't cover something yet.
If we don't cover your question, you can ask us to email you when we do.
A public, reviewed collection of questions and answers, with identifying details removed and shared only with your permission.

If something just feels off

It usually starts with a quiet sense that something isn't right. Maybe you saw your own doctor, or ended up in an emergency room. Often the blood and urine tests come back inside the “normal ranges,” so nothing gets flagged. The good clinicians still sense that something is off and send you further up the chain — and that is exactly the right move. No one doctor has seen every rare disease; knowing when to pass you along is the mark of a good one, not a failing.

If you have landed on this path, we want to help. And — strange as it sounds — you may be one of the lucky ones. Most people with these conditions aren't found until much later, when treatment is harder, more invasive, and more costly. Early is the best place to be standing, and you are here early.

From the first edition of the Book

From the first edition of the Book (8–11 September 2026): “The Book of Rare Diseases”.

There are no rare diseases, only rare, delayed diagnoses.

This site is new and still being built. Everything on it is real work and the sources are shown, but some areas are thin and you may find something wrong. If you do, say so. Nothing here replaces someone who can examine you.

A disease gets called rare because it is rarely found. The signs were usually there for years, in tests somebody already ordered. This book is about the finding.

Most people arrive at these pages carrying one phrase: chronic kidney disease. It is a true description and it names no cause. Two of the causes that get looked for last are inside that circle, and one of them can be the reason for the other.

Rare disease, or rare diagnosis?

When you are told a disease is rare, listen to the word. It is doing more work than you think. A disease is called rare partly because few people have it — and partly because few doctors go looking. The second half is the half that can change.

Both conditions in this book are examples. One of them, MGRS, was only named as a separate thing in 2012. A doctor who trained before that learned the underlying blood finding was harmless and needed only watching. The idea that it can quietly damage a kidney is newer than most of the careers treating it.

Two ways in

Start from what is happening to you — the index. Plain words, no disease names. Use this one if you are frightened, or if nobody has given you a name yet.

Or start from a name, below, if you already have one.

One chapter for each condition. Every chapter opens with the sentence a person actually arrives carrying, not the name of the disease.

I was told my kidneys are failing and nobody has said why Chronic kidney disease — the label most people are given. A stage number, a follow-up in six months, and no name for the cause.
My blood has an odd protein and my kidneys are getting worse MGRS — one doctor watches the protein, another watches the kidneys, and nobody is watching whether the first is doing the second.
My biopsy came back saying C3 C3 glomerulopathy — a word from the immune system on a kidney report, with no plain explanation attached.
My child is delayed, has seizures, and nobody can say why SYNGAP1-related disorder — one gene, a test that finds it, and a question that is usually never asked.
Itching and skin changes nobody has looked at properly Lichen sclerosus — treatable, and routinely missed for years, partly because of where on the body it is.
I started a statin and now my muscles ache Usually nothing much. Occasionally the start of something that damages the kidneys, and one cheap test tells them apart.

More chapters are being written. A chapter goes up when there is enough behind it to be worth your time, and not before.

What this is, and what it is not

What it is: what is known, where it came from, and the questions worth putting to the person treating you.

What it is not: an examination. Nothing here can tell you what is happening in your body. It can tell you what is worth asking.

Part of the Vermont Synergy Initiative. It costs nothing to use, and no one is ever turned away because of cost.