Hb Fontainebleau [alpha 21(B2)Ala----pro], a new silent mutant hemoglobin.

Hb Fontainebleau [alpha 21(B2)Ala----Pro] was found in a family of Italian origin. This new variant has electrophoretic properties identical to those of Hb A with the exception of isoelectrofocusing in which it migrates like Hb A1c. The introduction of a prolyl residue at the beginning of the B helix in the alpha chain does not lead to a change in the stability or oxygen binding properties of the hemoglobin molecule.