An unstable haemoglobin, Hb Tacoma beta30 (B12) arg leads to ser, detected at birth by the demonstration of red cell inclusions.

Abstract

Incomplete expression of human haemoglobin beta-chains at birth may lead to difficulty in the early demonstration of an inherited beta-chain variant. In this case, the rare unstable variant, Hb Tacoma beta30 (B12) arg leads to ser, although not present in cord blood in sufficient amounts to be easily detected by routine electrophoretic techniques, was readily shown to be present by the striking inclusions provoked by prolonged incubation of the neonatal red cells with new methylene blue.

The conserved Phe GH5 of importance for hemoglobin intersubunit contact is mutated in gadoid fish

“…Replacement of Arg with the smaller Lys residue containing only two N atoms caused slight anemia in Chinese Hb Kairouan (Arg31α- > Lys) mutants [ 23 ], while normal functional properties was found in the unstable Hb Prato (Arg31α- > Ser) mutant [ 24 ]. Corresponding Arg B12 mutations in the β globin are found in the unstable human Hb Tacoma (Arg30β- > Ser), but also in the rat zero β globin [ 25 , 26 ], while the mutant protein and transcript were undetectable in human Hb Monroe (Arg30β- > Thr) [ 27 ]. The importance of the interacting Phe GH5 was demonstrated by the polar Ser replacement in Hb Caruaru (Phe122β- > Ser) causing chronic haemolytic anaemia [ 28 ], but the stability and oxygen binding affinity of Hb Bushey (Phe122β- > Leu) were identical to those of HbA [ 29 ].…”