The Fugates, a family that lived in the hills of Kentucky, commonly known as the "Blue Fugates" or the Blue People of Kentucky, are notable for having been carriers of a genetic trait that led to the disease methemoglobinemia, which gives sufferers blue-tinged skin.
Martin Fugate and Elizabeth Smith who had married and settled near Hazard, Kentucky in around 1800, were both carriers of the recessive methemoglobinemia (met-H) gene, as was a nearby clan with whom the Fugates descendants intermarried. As a result, many descendants of the Fugates were born with met-H.
Descendants with the disease gene continued to live in the areas around Troublesome Creek and Ball Creek into the 20th century, eventually coming to the attention of the nurse Ruth Pendergrass and the hematologist Madison Cawein III, who made a detailed study of their condition and ancestry.
Cawein treated the family with methylene blue, which eased their symptoms and reduced the blue coloring of their skin.  He eventually published his research in the Archives of Internal Medicine in 1964.
As travel became easier in the 20th century, and families spread out over wider areas, the prevalence of the recessive gene in the local population reduced, and with it the probability of inheriting the disease.
Benjamin Stacy, born in 1975, is the last known descendant of the Fugates to have been born exhibiting the characteristic blue color of the disease, and lost his blue skin tone as he grew older.
It has been speculated that some other American sufferers of inherited methemoglobinemia may also have had Fugate ancestors, but searches for direct links have so far proved inconclusive.
- "Blue-skinned family baffled science for 150 years". MSN. 24 February 2012. Archived from the original on January 22, 2013. Retrieved 10 May 2013.
- Cathy Trost. "The Blue People of Troublesome Creek". Science 82, November, 1982
- Straight Dope article on the Fugates of Appalachia, an extended family of blue-skinned people
- "Rare disease turns mountaineers blue". Phoenix, Arizona: Arizona Republic. November 7, 1974. p. 12. Retrieved 3 April 2019 – via Newspapers.com.
- Susan Donaldson James (February 22, 2012). "Fugates of Kentucky: Skin Bluer than Lake Louise". ABC News. Retrieved 2014-10-04.
- Susan Donaldson James (March 8, 2012). "Blue People Look for Genetic Connection to Kentucky Fugates". ABC News. Retrieved 2014-10-04.
- Lyle E. Davis (January 19, 2006). "The Blue People of Troublesome Creek". The Paper.
- Cawein, M; Behlen Ch, 2nd; Lappat, E. J.; Cohn, J. E. (1964). "Hereditary Diaphorase Deficiency and Methemoglobinemia". Archives of Internal Medicine. 113: 578–85. doi:10.1001/archinte.1964.00280100086014. PMID 14109019.