Web: | mayocliniclabs.com |
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Email: | mcl@mayo.edu |
Telephone: | 800-533-1710 |
International: | +1 855-379-3115 |
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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 one 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)
This test is not useful for diagnosis or confirmation of alpha-thalassemia, the most common beta-thalassemias, or hemoglobin variants. It also does not detect nondeletional hereditary persistence of fetal hemoglobin.
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.
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
Polymerase Chain Reaction (PCR) Analysis/Multiplex Ligation-Dependent Probe Amplification (MLPA)