Re: Can a Caucasian have Bombay blood?

The classic Bombay phenotype has only been reported in those of Indian 
descent.  It is quite rare with an incidence of 1 in 250,000.  The bombay 
phenotype is characterized by mutations in fucosyltransferase. 
Fucosyltransferase is an enzyme that adds sugars to molecules exposed on 
the red blood cell surface.  These sugars are used to determine the ABO 
blood type.  Therefore a person with Bombay has the phenotype of O blood 
even though genetically they might have a different blood type.  Since 
these are independent those with Bombay blood type are not necessarily one 
blood type (they could be any).  There are similar phenomena to Bombat 
phenotype.  There is a para-Bombay phenotype in which the 
fucosyltransferase levels are greatly reduced.  This occurs in Chinese 
individuals with a frequency of 1 in 8,000.  Also the bombay phenotype is 
one of many elements of Rambam-Hasharom which is a genetic syndrome also 
characterized by mental retardation. IT is thought the genetic lesion here 
is quite large.