Rare discoveries that transformed medicine

Again and again, the study of a rare disease has unlocked a treatment that helps millions. Rare biology has a way of illuminating the whole.

There is a paradox at the heart of rare-disease research: some of the discoveries that help the most people begin with the study of conditions that affect very few.

Nature's experiments

Rare genetic diseases have been called “nature's experiments”, because a single altered gene can reveal, with unusual clarity, what that gene normally does.¹ Study the exception, and you often learn the rule.

A cholesterol story

Consider familial hypercholesterolemia, a rare inherited disorder of dangerously high cholesterol. Investigating its genetics led, in 2003, to the discovery of a gene called PCSK9.² That discovery opened the way to an entirely new class of cholesterol-lowering drugs, the PCSK9 inhibitors, which lower LDL cholesterol by 50 to 60% and now help enormous numbers of people, far beyond the rare condition where the story began.²

Study the rare exception, and you often learn the common rule.

The pattern repeats

It is a pattern that recurs throughout medicine: a rare disease exposes a biological pathway, and understanding that pathway yields a therapy of far wider use. The rare, in this sense, is a window into the universal.

Why it matters

It is one of the strongest arguments for taking rare disease seriously, not only for the 300 million people who live with one, but for the insights into human biology that ripple outward to everyone else.