The First Case of Hb G-Honolulu [α30(B11)Glu→Gln (GAG>CAG); HBA2:c.91G>A] Observed in Association with Hb S [β6(A3)Glu→Val, GAG>GTG] in a Healthy Italian Child

Abstract

We report the first observation of Hb G-Honolulu [α30(B11)Glu→Gln (GAG>CAG); HBA2:c.91G>A] in a Caucasian family and the first case of this variant to be found in association with Hb S [β6(A3)Glu→Val, GAG>GTG]. The proband was a healthy 4-year-old Italian boy. His chromatographic hemoglobin (Hb) pattern showed an abnormal peak having the typical retention time of Hb S (25.6% ), a second abnormal peak eluted soon after (13.6%) and a third minor peak eluted at the end of the run (6.5%). Identification of Hb variants were performed by peptide mapping using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Two abnormal peptides at m/z 765.1 and 922 were found, corresponding to the αT-4 and βT-1 peptides characteristic for Hb G-Honolulu and Hb S, respectively. The third minor abnormal peak presumably corresponded to the hybrid molecule (α(G-Honolulu)/β(S)). The concomitant presence of Hb G-Honolulu and Hb S does not seem to produce any relevant clinical manifestation.