Hb Bristol-Alesha presenting thalassemia-type hyperunstable hemoglobinopathy.

Hemoglobin (Hb) Bristol-Alesha is caused by a GTG --> ATG mutation at codon 67 in the Hb beta chain, resulting in abnormal beta globin chains with mutated molecules from normal beta67 valine (Val) to beta67 methionine (Met) or beta67 aspartate (Asp). We describe a Japanese child with this rare hemoglobinopathy and a very unstable Hb molecule phenotype. The diagnosis of hemolytic anemia was made when the patient was 6 months of age. Development of marked splenomegaly necessitated red blood cell transfusions twice a month. After splenectomy when the patient was 4 years of age, laboratory findings of hemolytic anemia became more prominent. Specific abnormal Hb molecules initially were not detected, and the alpha/beta globin synthesis ratio was abnormal at 2.22. After splenectomy, we identified the presence of abnormal beta-globin chains with a beta67Val:beta67Met:beta67Asp molecule ratio of 74:11:15. We speculate that the high fraction of the beta67Met molecule in this patient, compared with that in previously reported cases, caused extreme Hb instability, which resulted in thalassemic hyperunstable hemoglobinopathy and very severe clinical findings.