The M gamma chain of human fetal hemoglobin.

A new gamma chain of human fetal hemoglobin, the M gamma chain, has been detected by high performance liquid chromatography (HPLC). It is characterized by a Leu----Met replacement at position gamma 141; no other structural variations have been found. The M gamma chain has been observed in red cell lysates of subjects with a heterozygosity for one of many types of hereditary persistence of fetal hemoglobin (HPFH), in sickle cell anemia, and in a few cord blood samples. At present, the genetic cause of this newly discovered heterogeneity is not known; an infidelity in translation or the existence of an unrecognized gamma globin gene should be considered.