Bombay blood group contains
**Core Concept**
The Bombay blood group is a rare blood type characterized by the absence of H antigen on red blood cells, which is a precursor to the ABO blood group antigens. This condition is caused by a genetic mutation that affects the production of the H antigen, leading to its complete absence.
**Why the Correct Answer is Right**
The correct answer is related to the genetic mutation that affects the FUT1 gene, which codes for the alpha-1,2-fucosyltransferase enzyme responsible for adding the fucose molecule to the H antigen. The absence of this enzyme results in the complete absence of the H antigen on red blood cells, leading to the Bombay blood group phenotype. This condition is often associated with a severe hemolytic reaction when exposed to ABO blood group antibodies.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the genetic basis of the Bombay blood group.
**Option B:** This option is incorrect because it refers to a different blood group system, not the Bombay blood group.
**Option C:** This option is incorrect because it does not accurately describe the biochemical basis of the Bombay blood group.
**Clinical Pearl / High-Yield Fact**
The Bombay blood group is a rare but clinically significant condition that requires careful consideration when transfusing blood products to avoid severe hemolytic reactions.
**Correct Answer:** D.