There is a phenomenon in the genes of some people who made them be born blue. Yes the actual color blue. There has been entire families with the gene that made them all blue. There are also others who became blue due to a silver supplemental solution. The correct name for this condition is Argyria. Please read with detail to see their differences.
First I am going to address the phenomenon which is more common in nowadays society, due to ingestion of heavy metals, like silver (and perhaps others).
People who became blue due to heavy metal content in their blood:
The woman who turned blue due to Argyria, a rare side effect of a silver supplement called "colloidal silver"
"Methemoglobinemia can be acquired through use of certain drugs, or can be inherited through the presence of recessive genes. There have been reports of blue families or tribes through history that could be explained by inherited Methemoglobinemia. The best-documented of these is the Blue Fugates of Kentucky."
Blue People  by Miss Cellania - September 11, 2008 - 7:09 AM
Who is at risk of turning blue?
The people who were blue due to a gene, was caused by inbreeding, cousins married other cousins, son married an aunt, which made the problem only worse for these poor people. This happened a hundred years ago so they really didn't know better. Unless you yourself have the gene and intend to inbreed with someone who has the gene, you can't recreate this defect.
Now due to other causes, some people can turn blue. Anyone who uses supplements made out of silver, not approved to be sold as a drug in a pharmacy can develop Argyria. Colloidal Silver (common name) is not sold as a drug in pharmacies, due to it being illegal. However it is legal to sell it as a "dietary supplement".
The gene problem showed up in a family from Kentucky who lived more than a hundred years ago. These wonderful loving people were isolated for a century due to the fact that they were blue, the last of them (that carried the gene) was born in the 1970s:
Here are the reference articles, in two different locations in Wikipedia. Remember this phenomenon was caused by two totally different causes.
This is the case of blue people due to genetical defect:
"Methemoglobinemia is a disorder characterized by the presence of a higher than normal level of methemoglobin (metHb) in the blood. Methemoglobin is a form of hemoglobin that does not bind oxygen. When its concentration is elevated in red blood cells, tissue hypoxia can occur."
|Includes CC-BY-SA content from Wikipedia's Methemoglobinemia article (authors)|
This is the case of people who turn blue due to Silver:
Argyria (ISV from Greek: ἄργυρος argyros silver + -ia) is a condition caused by improper exposure to chemical forms of the element silver, silver dust or silver compounds.:858 The most dramatic symptom of argyria is that the skin becomes blue or bluish-grey colored.
|Includes CC-BY-SA content from Wikipedia's Argyria article (authors)|
See also Can colloidal silver turn people blue?