causes condition has contributing genetic variation causes molecular phenotype Sickle Cell Disease-S Beta Zero Thalassemia Hemoglobin S Beta-Zero Thalassemia Mutation HBB, GLU6VAL Hemoglobin Genotype S/Beta Zero Thalassaemia Request inclusion into relevant ontology None When one beta-globin gene carries the hemoglobin S mutation (beta6Glu>Val) whereas the other carries a null mutation, called beta-zero, because of the resulting inability to synthesize any beta-globin chain. S/Beta-Zero-Thalassemia S/Beta-Zero-Thal Genotype S/Beta-Zero-Thalassaemia Genotype Hemoglobin Genotype S/Beta Thalassemia Absent Hemoglobin A