Every rare disease tells a story. Understanding how one unfolds — how it develops and evolves — is often the first step toward treating it. A small genetic error, a malfunctioning cell or a breakdown in a biological process can set disease in motion. But for many rare conditions, the course of progression remains unwritten.  A groundbreaking natural history study led by researchers at Mayo Clinic’s Center for Individualized Medicine and Department of Clinical Genomics aims to…