Haptoglobin Subtypes in Tuscany (Italy)

The genetic polymorphism of haptoglobin (HP) has been first observed, through starch gel electrophoresis, by Smithies et al (1955), who demonstrated three common phenotypes: HP 1, HP2-1 and HP2. The HP-α chain, which carries the polymorphism, has subsequently been shown to exist in several additional allelic forms (“subtypes”) - 1S, 1F, 2FS, 2FF and 2SS - giving rise to three different HP1, six different HP2-1 and six different HP2 phenotypes. Only in the last few years, however, methods suitable for routine HP subtyping have been developed.