has causal or contributing genetic variation HBB, GLU6VAL HBB, VAL23ILE Hemoglobin S-Antilles A form of hemoglobin caused by two mutations in its beta-chains, the classic beta S mutation (beta 6 Glu>Val) and beta 23 Val>Ile. Hemoglobin S-Antilles has the same electrophoretic mobility as Hemoglobin S but a distinct isoelectric focus and produces sickling in the carriers of the Hb A/S Antilles trait. SCDO (Jade Hotchkiss) Few but definitions not freely available Request inclusion into the HPO, below "Abnormal Hemoglobin"/"Sickling Hemoglobin with Two Beta-Globin Gene Substitutions". Sickling Hemoglobin with Two Beta-Globin Gene Substitutions