Test Catalog

Test ID: WBDD    
Beta-Globin Cluster Locus Deletion/Duplication

Useful For Suggests clinical disorders or settings where the test may be helpful

Determining the etiology of hereditary persistence of fetal hemoglobin (HPFH), or delta-beta-thalassemia


Diagnosing less common causes of beta-thalassemia;these large deletional beta-thalassemia mutations result in elevated hemoglobin (Hb) A2  and usually have slightly elevated Hb F levels


Distinguishing homozygous Hb S disease from a compound heterozygous Hb S/large beta-globin cluster deletion disorder (ie, Hb S/beta zero thalassemia, Hb S/delta beta zero thalassemia, Hb S/HPFH, Hb S/gamma-delta-beta-thalassemia)


Diagnosing complex thalassemias where the beta-globin gene and 1 or more of the other genes in the beta-globin cluster have been deleted


Evaluating and classifying unexplained increased Hb F percentages


Evaluating microcytic neonatal anemia


Evaluating unexplained long standing microcytosis in the setting of normal iron studies and negative alpha-thalassemia testing/normal Hb A2 percentages


Confirming gene fusion hemoglobin variants such as Hb Lepore and Hb P-Nilotic


Confirming homozygosity vs hemizygosity of mutations in the beta-like genes (HBB, HBD, HBG1, HBG2)

Genetics Test Information Provides information that may help with selection of the correct genetic test or proper submission of the test request

A hemoglobin electrophoresis evaluation (HBELC / Hemoglobin Electrophoresis Cascade, Blood) is always indicated prior to beta-globin cluster locus deletion and duplication testing because these conditions can be complex and protein data allows accurate classification of the patient phenotype.


This test can be used to identify a variety of conditions (listed below) that involve large deletions of the beta-globin gene cluster. These mutations will not be detected by DNA sequencing of the beta-globin gene.

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

This test is recommended to identify a variety of conditions involving large deletions or duplications within the beta-globin gene cluster locus region including:

-Identifying large deletions causing increased hemoglobin (Hb) F levels such as hereditary persistence of fetal hemoglobin (HPFH), delta-beta-thalassemias, and gamma-delta-beta-thalassemia

-Identifying beta-thalassemia conditions in cases where beta gene sequencing did not find a beta-thalassemia mutation

-Confirming gene fusion hemoglobin variants such as Hb Lepore and Hb P-Nilotic

-Investigating newborns with unexplained microcytic anemia that is suspected to be caused by epsilon-gamma-delta-beta-thalassemia

-Confirming homozygosity vs hemizygosity of mutations in the beta-like genes (HBB, HBD, HBG1, HBG2)

-Investigating individuals older than 12 months of age with unexplained microcytosis and normal hemoglobin electrophoresis for whom more common causes of microcytosis such as iron deficiency and alpha-thalassemia have been excluded

Special Instructions Library of PDFs including pertinent information and forms related to the test

Method Name A short description of the method used to perform the test

Polymerase Chain Reaction (PCR) Analysis/Multiplex Ligation-Dependent Probe Amplification (MLPA)

NY State Available Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name Lists a shorter or abbreviated version of the Published Name for a test

Beta Globin Cluster Locus Del/Dup

Aliases Lists additional common names for a test, as an aid in searching

MLPA beta globin cluster locus
Beta globin cluster locus deletion/duplication
Beta globin deletion
Beta thalassemia deletion
Beta globin complex deletions
Beta cluster del/dup