It is important to be cautious in predicting the ABO blood type of
children based on the phenotype of their parents. This is due to the fact that
a third antigen (H) on the surface of red cell can prevent the expected ABO
blood group from occurring. Normally if an A blood type mother has an O type
child, the father is expected to be type O or at least to carry the O allele
(OO, AO, or BO genotype). The H antigen is a precursor to the A antigens, for
instance, the B allele must be present to produce the B enzymes that modifies
the H antigen to become the B antigen. It is the same for the A allele. However
if only one recessive allele for the H antigen is inherited (hh), the H antigen
will not be produced, the result is an O phenotype by default since a lack of A
and B antigen is the O type.
children based on the phenotype of their parents. This is due to the fact that
a third antigen (H) on the surface of red cell can prevent the expected ABO
blood group from occurring. Normally if an A blood type mother has an O type
child, the father is expected to be type O or at least to carry the O allele
(OO, AO, or BO genotype). The H antigen is a precursor to the A antigens, for
instance, the B allele must be present to produce the B enzymes that modifies
the H antigen to become the B antigen. It is the same for the A allele. However
if only one recessive allele for the H antigen is inherited (hh), the H antigen
will not be produced, the result is an O phenotype by default since a lack of A
and B antigen is the O type.
This possible phenotype result, has be referred to as a Bombay
phenotype, this is because it was first discovered in the Indian city (Dennis,
2012).
phenotype, this is because it was first discovered in the Indian city (Dennis,
2012).