Summary
Overview
Josh and Chuck explore fascinating cases of people with blue or silver-tinted skin, focusing on the Fugate family of Kentucky who suffered from methemoglobinemia, a rare genetic blood disorder. They also discuss argyria, a condition caused by excessive silver exposure, and touch on how skin color adapts over generations based on UV exposure.
The Blue Fugates of Kentucky
The episode opens with the remarkable story of Martin Fugate, a French orphan who settled in Kentucky's Blue Hills in 1820. Against astronomical odds, he and his wife Elizabeth Smith both carried a rare genetic mutation that, when combined, produced children with strikingly blue skin. Four of their seven children were born with dark blue skin, not just a bluish tint. The family became isolated in Appalachia, and their intermarriage with relatives led to a small regional population of blue-skinned families that persisted for generations.
- Martin Fugate came from France to Kentucky in 1820 and married Elizabeth Smith, a redheaded American with very pale skin
- The chance of having the genetic mutation is about one in 100,000, but with interbreeding it can increase to one in eight
- Four of their seven children were born with dark blue skin due to both parents carrying the mutation
- The family became isolated and family members intermarried, spreading the condition through the local population
" Once you start inbreeding, which can happen in the 1800s in the ruralness of Kentucky, he said that can go down all the way to like one in eight chance. "
" This was like straight up blue kids. I've even seen them described as dark blue, not even a bluish hue or tint or tinge. Dark blue skinned children. "
The Science Behind Methemoglobinemia
The hosts explain the biological mechanism behind the Fugates' blue skin. Unlike typical skin color changes related to melanin, methemoglobinemia is a blood disorder where the body lacks sufficient amounts of an enzyme with an impressively long name that converts methemoglobin into oxygen-carrying hemoglobin. When methemoglobins build up in the blood beyond about 1% of total blood volume, the blood appears blue through translucent skin. Surprisingly, the condition doesn't cause significant health problems despite affecting oxygen transport.
- Blood is red due to hemoglobin containing iron atoms that bind with oxygen; the childhood belief that blood is blue until exposed to air is false
- Methemoglobin contains oxidized 'rusted' iron that cannot bind to oxygen, making it useless for oxygen transport
- The body naturally produces the enzyme 'reduced nicotinamide adenine dinucleotide cytochrome B5 reductase' which converts methemoglobin to hemoglobin
- Only about 1% methemoglobin in the blood is needed to turn skin blue, leaving 99% normal hemoglobin for oxygen transport
" The enzyme is called reduced nicotinamide adenine dinucleotide cytochrome B5 reductase. One of the great all-time names. "
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