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

We report the first observation of Hb G-Honolulu [alpha 30(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 [beta 6(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 alpha T-4 and beta T-1 peptides characteristic for Hb G-Honolulu and Hb S, respectively. The third minor abnormal peak presumably corresponded to the hybrid molecule (alpha(G-Honolulu)/beta(S)). The concomitant presence of Hb G-Honolulu and Hb S does not seem to produce any relevant clinical manifestation.