The Indian blood group system (In) is named because 4% of the population in India possess it . It is a classification of blood based on the presence or absence of inherited antigens that reside within the CD44 molecule that is expressed on the surface of blood cells. Most individuals express the Inb antigen that results from an arginine residue at position 46 of CD44 . The Ina blood type results from a substitution proline for arginine at this same position.
- ^ Telen MJ, Udani M, Washington MK, Levesque MC, Lloyd E, Rao N (March 1996). "A blood group-related polymorphism of CD44 abolishes a hyaluronan-binding consensus sequence without preventing hyaluronan binding". J. Biol. Chem. 271 (12): 7147–53. doi:10.1074/jbc.271.12.7147. PMID 8636151.