Transcript Blue People of Kentucky PPT

The Blue People of Kentucky
A Study in Genetics:
This is a colorized
black and white
photo of a family
with some of the
family members
having blue skin.
abcnews.com

Meet the Fugates…
 Martin Fugate had methemoglobinemia. He also had
four children with the disorder.
Background info
 In normal blood hemoglobin is an abundant protein
that carries oxygen. Some of the hemoglobin is in
an altered form called methemoglobin.
Methemoglobin carries almost no oxygen and in
people with normal blood there is very little
methemoglobin in their red blood cells. People with
methemoglobinemia have too much
methemoglobin in their blood which gives their skin
a blue color.
methemoglobinemia
 People with this disorder have an enzyme that does not
work normally. The enzyme, cytochrome b5 reductase,
is responsible for changing methemoglobin into
hemoglobin.
The Fugates…
 Martin married a carrier of the disease in the early
1800s and they bore seven children; four of which
were blue.
 The condition is inherited as a recessive trait and
would appear most often in a small population. In
this population they had methemoglobinemia,
type I.
Fugate Pedigree
Geographic Isolation…
 The people of this community in Kentucky,
Troublesome Creek were isolated from the rest of the
country. When the town was settled there were no
roads, making it hard to get out and people tended to
intermarry.
 One of Martin’s sons married his maternal aunt and
100 years later Benjy Stacey was born (1975). He was
blue at birth and doctors wanted to give him a
transfusion until someone mentioned blue skin color
ran in the family. His skin turned normal in a few days.
Geographic Isolation
 As railroads and development swept
through, the blue Fugates started moving
out of Troublesome Creek and marrying
other people.
 The inherited blue began to disappear as
the recessive gene spread to families where
it is unlikely to be paired to a similar gene.
Methemoglobinemia
 There are several causes of methemoglobinemia.
The most common is acquired by exposure to
certain chemicals like benzene or certain
antibiotics. It disappears when the chemicals are
gone.
 The Fugates had an inherited form of the disease.
Oddly enough, the treatment for the disease was a
blue dye called methylene blue. When given a
small dose the patients skin became normal.
Assignment
 We have identified methemoglobinemia as an
autosomal recessive disorder. Go to the web site:
 http://omim.org
 This website, Online Mendelian Inheritance in Man,
is a database with a wealth of information about
genetic conditions.
 Follow your instructions on your worksheet.