|
|
| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Alpha Thalassemia Sequencing Panel with CNV Detection
MessageSent to Prevention Genetics via Quest
Test Code
ALPHA THALASSEMIA SEQ-CNV(O)
Alias/See Also
Prevention Genetics (#6090)
Includes
HBA1, HBA2
Preferred Specimen
2 whole blood lavender top tubes
Minimum Volume
3 mL
Transport Temperature
Room Temperature
Specimen Stability
Room temperature: 48 hours
Refrigerated: 1 week
Refrigerated: 1 week
Methodology
Bi-Directional Sanger Sequencing and Multiplex Ligation-Dependent Probe Amplification Assay
Report Available
Great majority of tests are completed within 20 days.
Reference Range
Provided with patient report in CPRS.
Clinical Significance
Hemoglobin A, the main form of hemoglobin, is a polypeptide comprised of two alpha and two beta chains. Alpha chains are encoded through the HBA1 and HBA2 genes. Defects in these genes result in alpha thalassemia, which is a common hemoglobin disorder commonly found in African and Asian populations. Carrier frequencies are >1% due to a selective advantage of malaria resistance in these individuals. There are four clinical conditions ranging in severity from asymptomatic to hydrops fetalis: silent carrier, alpha thalassemia trait, hemoglobin H (HbH), and hemoglobin Bart hydrops fetalis (Hb Bart). Disease severity is correlated to the degree of impaired alpha chain production (Origa and Moi. 2016. PubMed ID: 20301608; Harteveld and Higgs. 2010. PubMed ID: 20507641).
The two main clinical forms of alpha thalassemia are Hb Bart and HbH. Hb Bart syndrome is a neonatal lethal disease characterized by pleural and pericardial effusions, severe hypochromic anemia, ascites, and generalized edema. HbH disease, also referred to as alpha thalassemia intermedia, is characterized by microcytic hypochromic anemia, splenomegaly, jaundice, and in some cases skeletal changes primarily affecting facial features. Onset for HbH ranges from first years of life to adulthood. HbH individuals may also develop gallstones, have iron overload, or acute hemolytic episodes during infections or in response to oxidant drugs. In more severe forms HbH individuals may require blood transfusions. Patients with alpha thalassemia trait may have mild anemia, but are largely symptomatic (Origa and moi. 2016. PubMed ID: 20301608; Harteveld and Higgs. 2010. PubMed ID: 20507641; Galanello and Cao. 2011. PubMed ID: 21381239).
The two main clinical forms of alpha thalassemia are Hb Bart and HbH. Hb Bart syndrome is a neonatal lethal disease characterized by pleural and pericardial effusions, severe hypochromic anemia, ascites, and generalized edema. HbH disease, also referred to as alpha thalassemia intermedia, is characterized by microcytic hypochromic anemia, splenomegaly, jaundice, and in some cases skeletal changes primarily affecting facial features. Onset for HbH ranges from first years of life to adulthood. HbH individuals may also develop gallstones, have iron overload, or acute hemolytic episodes during infections or in response to oxidant drugs. In more severe forms HbH individuals may require blood transfusions. Patients with alpha thalassemia trait may have mild anemia, but are largely symptomatic (Origa and moi. 2016. PubMed ID: 20301608; Harteveld and Higgs. 2010. PubMed ID: 20507641; Galanello and Cao. 2011. PubMed ID: 21381239).
Performing Laboratory
Prevention Genetics
3800 S Business Park Ave
Marshfield, WI 54449
Additional Information
Link to Prevention Genetics Test Catalog
Last Updated: February 28, 2018
