Bombay blood type

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The Hh antigen system

The Bombay blood group , also known as the Bombay phenotype , is a very rare blood group of the AB0 system that is owned by around 20,000 people, most of them in India . People with this blood group are only allowed to receive blood donations from other people with this genetic defect .

Causes and effects

Affected persons do not express the precursor substance H, an antigen on the surface of the red blood cells ( erythrocytes ). This fact leads to blood group  0. For this reason they do not agglutinate (that is, “clump”) with the A and B antisera from the AB0 system of blood groups. The blood group of those affected is 0 and the genotype is hh sese . The Bombay blood group is usually marked with 0 h . The gene of the Bombay blood group is on chromosome 19 .

The cause of the lack of the precursor substance H is a genetic defect, for example in leukocyte adhesion defects type II . Regardless of the inheritance of the AB0 type, the Bombay type reacts neither with A nor B antibodies (phenotypically blood group 0). On the other hand, it reacts with blood group 0 (phenotypically anti-0) because the precursor substance H occurs in every carrier of AB0 and, in the Bombay type, antibodies against the precursor substance were formed very early in life. Thus, for those affected, only an autologous blood donation or donated blood from people with the same genetic defect is possible.


When testing for blood groups, tests for rare antibodies are now carried out regularly. Their positive result must be noted individually with the clinical indication of the blood group. These patients can only be given blood from their own blood or blood from other carriers with the same characteristics. The frequency of anti-H-positive carriers of the Bombay-type trait is 1: 300,000. A frequency of 1 in 7,600 is observed in parts of India. A high level of consanguinity was observed among the parents of the Bombay phenotype. This phenotype was first discovered in 1952 in what was then Bombay (now Mumbai) by YM Bhende and others, which led to the naming.

Individual evidence

  1. JS O'Donnell, TA McKinnon et al. a .: Bombay phenotype is associated with reduced plasma VWF levels and an increased susceptibility to ADAMTS13 proteolysis. In: Blood. Volume 106, Number 6, September 2005, pp. 1988-1991, ISSN  0006-4971 . doi: 10.1182 / blood-2005-02-0792 . PMID 15886321 .
  2. YM Bhende, CK Deshpande et al. a .: A "new" blood group character related to the ABO system. In: Lancet. Volume 1, Number 6714, May 1952, pp. 903-904, ISSN  0140-6736 . PMID 14918471 .

further reading