When popular YouTube star Adalia Rose died earlier this year, she looked like a diminutive, sickly woman in her 80s. In reality she was only 15 years old, a victim of progeria, an extremely rare genetic disorder caused by a single mutation in one of 3 million base pairs that make up human DNA. Completely normal in mind and spirit, children with progeria age at a very rapid pace, typically dying in their teenage years.