First case of a single heterozygote of an abnormal hemoglobin, Hb Stanmore, [β111(G13)Val→Ala]

We describe a hemoglobin β-chain mutant detected incidentally in an unusual profile of glycated hemoglobin (HbA1c) measured by ion-exchange HPLC. Analysis of intact globin by electrospray ionization mass spectrometry (ESI-MS) and peptide analysis by on-line HPLC-ESI-MS-MS revealed the substitution, [β111(G13)Val→Ala], which was confirmed by DNA analysis. This was the second case of Hb Stanmore. As the first case combined β0-thalassemia, and the family study in that case showed no case of Hb Stanmore without combined thalassemia, the case presented here is the first case of single heterozygote, and the first Japanese case. Hb Stanmore is isoelectrophoretically silent with only mild clinical symptoms, although stability by isopropanol test was positive.