Key Information
In the 5th century, in early medieval Ireland, Conall Gulban, an Irish king, gave his name to an area of land at the northwest tip of the Irish coast. His kingdom was called Tir Chonall, the "land of Conall"-or, today, Donegal.
Somewhere along the king's descendant line, known as Cenel Conaill or "kindred of Conall," it's thought that a mistake arose in a scion's genome-specifically, a mutation of a gene responsible for producing a protein called transthyretin (TTR). The genetic error resulted in the birth of a rare condition known as hereditary transthyretin (ATTR) amyloidosis.
The TTR protein is made predominantly in the liver and is responsible for shuttling vitamin A and a hormone called thyroxine around the body. But in those with hereditary ATTR amyloidosis, the genetic mutation produces a botched version of it. This misshapen TTR aggregates and leaves clumps of amyloid, another protein, in tissues around the body-mostly the heart muscles and the nerves.