Modern Genetics Solves 150 Year Mystery

Recently, I read about a family that lived in Troublesome Creek, Kentucky 150 years ago with blue skin. Martin Fugate passed on his blue skin to four of his children who also had children with blue skin. After years of wondering, the mystery has finally been solved thanks to modern genetics. It turns out that these blue-skinned people had Methemoglobinemia, a blood disorder in which too much methomoglobin is produced. Methomoglobinemia is a recessive genetic disorder which explains how rare it is today. Troublesome Creek had no railroads, leading to almost no contact with the outside world. This led to cousins and neighbors marrying, keeping the trait much more prevalent than in a larger society.