causes condition has contributing genetic variation causes molecular phenotype Hemoglobin D Trait Genotype Hemoglobin D HBB, SER9TYR HBB, GLU121GLN HBB, GLY16ARG HBB, ASN19LYS HBB, GLU22GLN HBB, GLU22VAL HBB, THR87LYS HBB, GLU121ALA Hemoglobin Genotype AD AD Genotype A genotype whereby one HBB allele produces hemoglobin beta chains for normal adult hemoglobin and the other produces the abnormal hemoglobin beta chains for hemoglobin D. Individuals with this genotype are known to be carriers of the hemoglobin D trait. None SCDO (Clair Ingram) Haemoglobin Genotype AD AD Hemoglobin Genotype Hemoglobin D Trait Genotype