Hb Port Huron [alpha 56 (E5)Lys----ARG]: a new alpha chain variant.

We have determined the structural abnormality of a putative Hb E detected in an African-American family with no apparent Asian ancestry. The tryptic peptide map performed by high performance liquid chromatography showed that the electrophoretic variant was indeed Hb E [beta 26 (B8)Glu----Lys]. In addition, the tryptic map showed an abnormal peptide adjacent to the alpha T-6 peptide. The amino acid analysis and confirmatory restriction analysis of the DNA showed that a second mutation was also present, characterized by a substitution of arginine for lysine at residue 56 of the alpha chain. The variant is clinically silent and has been named Hb Port Huron for the city in Michigan where the family resides.