• It is a serum protein with 2 globulins which is concerned with transport of free hemoglobin (it combines with hemoglobin in plasma) to liver for breakdown of haem and ultimate production of bile salts, bilirubin and biliverdin. Thus it prevents HB from damaging kidneys.
• Electrophoretic study
It shows three band types
(1) Type 1-1 (single strong band)
(2) Type 2-2 (a series of slowly moving bands)(No strong band)
(3) Type 2-1 (a weak band like 1-1 along with number of slow moving bands) : co-dominance
Genotypes and phenotypes:- above patterns are inherited. Two alleles Hpl and Hp2 . These follow Mendelian inheritance.
| Genotype | Phenotype |
| Hp1 Hp1 | Band 1-1 |
| Hp2 Hp2 | Band 2- 2 |
| Hp1 Hp2 | Band 1- 2 |
• Population Variations : Incidence of Hpl gene
- (1) Western Europe- around 40%
- (2) Tropical Africa- Higher: 60%
- (3) South Africa- lower values
- (4) Some African Populations- 20-30% show no haptoglobins- ahaptoglobinemic (HpO)
- (5) Asia- lower (10-20%) (India, China, Japan and also Australia)
- Haptoglobin polymorphism is maintained by heterosis.
- Increased proportions have been found in a variety of inflammations and infections.
- Worldwide distribution: Its frequency increases from India to North America through Siberia on one hand and India to Western & Northern Europe on other hand