Can B+ and O− parents have a B-ve blood group child?

Hi,

Welcome to the icliniq.com

I understand your concern.

This scenario presents an interesting case study in blood group inheritance. Your father's B-positive blood type indicates the presence of both B and rhesus D antigen-positive alleles (B RhD+). Further, your mother's O-negative blood type signifies the presence of two O alleles (OO RhD-). However, yours exhibits a B-negative blood type, seemingly defying conventional inheritance patterns.

The possible explanations for this may be:

1. Rh factor mismatch: In Rh-incompatible pregnancies, the RhD-negative mother can develop antibodies against the RhD-positive baby's blood. However, the daughter's B-negative blood implies she inherited the RhD-negative allele from her mother, preventing RhD incompatibility and its associated complications.

2. Father's genotype: The father must be a carrier of both B and O alleles (BO RhD+) to explain the daughter's blood type. This is because:

   • The mother can only pass on the O allele to her offspring.

   • The daughter's B-negative blood indicates receiving the B allele from her father.

   • The father's B-positive blood implies the presence of at least one B allele.

3. Incomplete dominance: The B allele is typically dominant over the O allele. However, in rare instances, incomplete dominance might occur, where the B allele does not completely suppress the expression of the O allele, leading to the B-negative phenotype.

I recommend that you consult with a medical professional or genetic counselor to provide a more definitive explanation and address any potential implications. They can analyze the specific blood types, medical history, and relevant genetic testing (if available) to offer a tailored interpretation and address any concerns.

I hope this answers your query.

Thank you.