Alpha-Globin Gene Deletion or Duplication

Consider eliminating iron deficiency anemia as a possibility.

In the absence of iron deficiency, there may be other genetic causes for abnormal RBC indices and HPLC results. Pathogenic variants such as point mutations in the alpha-1 and alpha-2 genes may be present. Alpha-Globin Gene Sequencing (test code 16116X [16117X for NY]) can detect pathogenic variants in these genes.

To discuss the patient or additional testing options, please call Quest Genomics Client Services at 1-866.GENE.INFO (1-866-436-3463) to speak with a genomic science specialist.

For a pregnancy to be at risk, both parents must be carriers of a pathogenic variant for thalassemia. For example, if one parent carries an alpha-globin triplication (5 alpha-globin gene copies) and the other parent carries a beta-zero pathogenic variant, the fetus could be at risk for beta-thalassemia intermedia. The partner should be screened to determine his/her hemoglobinopathy carrier status (Hemoglobinopathy Evaluation, test code 35489X). Molecular genetic testing may also be appropriate for the partner.

To discuss the patient or additional testing options, please call Quest Genomics Client Services at 1-866.GENE.INFO (1-866-436-3463) to speak with a genomic science specialist.

For family planning purposes, it is important to determine which gene deletions are present and to distinguish whether the deletions are in cis or in trans. The Alpha-Globin Common Mutation Analysis test (test code 11175) can detect the 7 most common deletions and identify whether the deletions are in cis or in trans. This, in addition to the partner’s alpha-thalassemia carrier status, will help assess whether a fetus could be at risk for alpha-thalassemia major (hydrops fetalis, a 4-gene deletion) or hemoglobin H disease.