causes condition has contributing genetic variation causes molecular phenotype Hemoglobin S Sickle Cell Trait HBB, GLU6VAL SCD Genotype Hemoglobin Genotype AS A genotype whereby one HBB allele produces hemoglobin beta chains for normal adult hemoglobin and the other produces the abnormal hemoglobin beta chains of hemoglobin S. Individuals with this genotype are known to be carriers of the sickle cell trait. Sickle Cell Trait Genotype Request inclusion into relevant ontology SCDO None Haemoglobin Genotype AS