Earlier
this year, attention was brought to the historic Blue People of
Kentucky. Located in the Appalachian mountains of eastern Kentucky, some
members of the Fugate family were maligned with an inherited type of
blood disorder called Methemoglobinemia that caused them to appear blue.
*
Initially noted in the early 20th century, the occurrence of the disorder was due to the geographical isolatio
n
of the inhabitants. First cousins who were carriers married each other
and passed on the recessive genes to their children. After population
growth in the state brought new inhabitants to the area, the disorder
slowly disappeared.
Methemoglobinemia is a gene disorder that
affects the amount of methoglobin (a type of hemoglobin) that is
produced in the body. Hemoglobin is the molecule responsible for
distributing oxygen in the body via red blood cells. Due to the
offending gene, the sufferers of the disorder are unable to sufficiently
release oxygen to body tissues, which can create a blue color.
There are two forms of inherited Methemoglobinemia. Caused by a
recessive gene, it requires getting the gene from both parents to
present symptoms. There are two types of inherited Methomoglobinemia:
type 1 occurs when the enzyme responsible for releasing the oxygen is
absent in RBCs (and causes the blue color), and type 2 occurs when the
enzyme doesn’t work in the body at all (and can be fatal).
A
defective hemoglobin molecule causes the second form. Called hemoglobin M
disease, it only requires one copy of the gene for a person to be
affected. Consuming or being exposed to certain chemicals and drugs can
also cause people to acquire Methemoglobinemia.
Fortunately,
for people afflicted with this disorder, treatments are now available
including Methylene blue, ascorbic acid, hyperbaric chamber visits, and
blood transfusions.
*Interestingly, if you preform a Punnett
Square on the family in the picture to this post, the genotype of the
father would be rr (afflicted) and the genotype of the mother would be
Rr (carrier). The resulting expected offspring would be 50% Rr and 50%
rr. There are seven children in the picture, and assuming these are the
couple’s genetic children, the observed ratio is 1.3:1.
http://www.nclark.net/
http://www.ncbi.nlm.nih.gov/
Picture provided by: http://www.nclark.net/
Earlier
this year, attention was brought to the historic Blue People of
Kentucky. Located in the Appalachian mountains of eastern Kentucky, some
members of the Fugate family were maligned with an inherited type of
blood disorder called Methemoglobinemia that caused them to appear blue.
*
Initially noted in the early 20th century, the occurrence of the disorder was due to the geographical isolatio
Initially noted in the early 20th century, the occurrence of the disorder was due to the geographical isolatio
n
of the inhabitants. First cousins who were carriers married each other
and passed on the recessive genes to their children. After population
growth in the state brought new inhabitants to the area, the disorder
slowly disappeared.
Methemoglobinemia is a gene disorder that affects the amount of methoglobin (a type of hemoglobin) that is produced in the body. Hemoglobin is the molecule responsible for distributing oxygen in the body via red blood cells. Due to the offending gene, the sufferers of the disorder are unable to sufficiently release oxygen to body tissues, which can create a blue color.
There are two forms of inherited Methemoglobinemia. Caused by a recessive gene, it requires getting the gene from both parents to present symptoms. There are two types of inherited Methomoglobinemia: type 1 occurs when the enzyme responsible for releasing the oxygen is absent in RBCs (and causes the blue color), and type 2 occurs when the enzyme doesn’t work in the body at all (and can be fatal).
A defective hemoglobin molecule causes the second form. Called hemoglobin M disease, it only requires one copy of the gene for a person to be affected. Consuming or being exposed to certain chemicals and drugs can also cause people to acquire Methemoglobinemia.
Fortunately, for people afflicted with this disorder, treatments are now available including Methylene blue, ascorbic acid, hyperbaric chamber visits, and blood transfusions.
*Interestingly, if you preform a Punnett Square on the family in the picture to this post, the genotype of the father would be rr (afflicted) and the genotype of the mother would be Rr (carrier). The resulting expected offspring would be 50% Rr and 50% rr. There are seven children in the picture, and assuming these are the couple’s genetic children, the observed ratio is 1.3:1.
http://www.nclark.net/
http://www.ncbi.nlm.nih.gov/
Picture provided by: http://www.nclark.net/
Methemoglobinemia is a gene disorder that affects the amount of methoglobin (a type of hemoglobin) that is produced in the body. Hemoglobin is the molecule responsible for distributing oxygen in the body via red blood cells. Due to the offending gene, the sufferers of the disorder are unable to sufficiently release oxygen to body tissues, which can create a blue color.
There are two forms of inherited Methemoglobinemia. Caused by a recessive gene, it requires getting the gene from both parents to present symptoms. There are two types of inherited Methomoglobinemia: type 1 occurs when the enzyme responsible for releasing the oxygen is absent in RBCs (and causes the blue color), and type 2 occurs when the enzyme doesn’t work in the body at all (and can be fatal).
A defective hemoglobin molecule causes the second form. Called hemoglobin M disease, it only requires one copy of the gene for a person to be affected. Consuming or being exposed to certain chemicals and drugs can also cause people to acquire Methemoglobinemia.
Fortunately, for people afflicted with this disorder, treatments are now available including Methylene blue, ascorbic acid, hyperbaric chamber visits, and blood transfusions.
*Interestingly, if you preform a Punnett Square on the family in the picture to this post, the genotype of the father would be rr (afflicted) and the genotype of the mother would be Rr (carrier). The resulting expected offspring would be 50% Rr and 50% rr. There are seven children in the picture, and assuming these are the couple’s genetic children, the observed ratio is 1.3:1.
http://www.nclark.net/
http://www.ncbi.nlm.nih.gov/
Picture provided by: http://www.nclark.net/
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