Number of Panel Genes2

This test is designed to detect carriers of alpha thalassemia. Alpha thalassemia refers to a group of blood disorders that results from deficiency of functional hemoglobin typically due to decrease in the production of alpha globin chains. Individuals generally have four copies of the alpha globin genes (2 copies of HBA1 and 2 copies of HBA2). Silent carriers of alpha-thalassemia have three functional copies of the alpha globin genes and are not expected to manifest symptoms.

This test is designed to detect carriers of alpha thalassemia. Alpha thalassemia refers to a group of blood disorders that results from deficiency of functional hemoglobin typically due to decrease in the production of alpha globin chains. Individuals generally have four copies of the alpha globin genes (2 copies of HBA1 and 2 copies of HBA2). Silent carriers of alpha-thalassemia have three functional copies of the alpha globin genes and are not expected to manifest symptoms. Individuals with alpha thalassemia trait have two functional copies of the alpha globin gene and may have mild anemia which cannot be treated with iron. The clinically significant forms of alpha thalassemia are hemoglobin H (HbH) disease and hemoglobin Bart hydrops fetalis (Hb Bart) syndrome. Hemoglobin H disease occurs (MIM 613978) in individuals with only one functional copy of the alpha globin genes. HbH disease usually presents in early childhood and symptoms include hemolytic anemia, splenomegaly, mild jaundice, and bone changes. Hb Bart syndrome (MIM 236750) is a severe disorder which occurs when no functional copies of the alpha globin genes are present. Hb Bart syndrome is characterized by fetal onset generalized edema, severe anemia, hepatosplenomegaly, and usually death in the neonatal period. Complications, such as preeclampsia, premature delivery, and antepartum hemorrhage are common during pregnancy with a baby affected by Hb Bart syndrome. Blood transfusions, including in utero transfusions for Hb Bart syndrome, may be used as treatment for these disorders. The most common pathogenic variants causing alpha-thalassemia are large deletions of the HBA1 (NM_000558) and/or HBA2 (NM_000517) genes. Silent carriers and individuals with alpha-thalassemia trait are at risk of having a child with HbH syndrome. Additionally, individuals with alpha-thalassemia trait are at risk of having a child with Hb Bart syndrome if they have two functional copies of alpha globin on one chromosome and zero active copies of alpha globin on the other chromosome (--/%u03B1%u03B1). If one reproductive partner is a silent carrier and the other has alpha-thalassemia trait with a (--/%u03B1%u03B1) configuration, the risk for HbH in their children is 25%. When both reproductive partners have alpha-thalassemia trait, the risk for a child with HbH is 50% if one partner has a (--/%u03B1%u03B1) configuration and the risk for a child with Hb Bart syndrome is 25% if both partners have a (--/%u03B1%u03B1) configuration. Alpha thalassemia trait is common in Southeast Asian, African, West Indian, and Mediterranean populations with individuals of Southeast Asian descent more likely to have the (--/%u03B1%u03B1) configuration. This test can detect 0, 1, 2, 3, and 4 copies of HBA1 and HBA2 but the number of copies on each allele is not determined. Co-inheritance of abnormalities involving other hemoglobin genes may modify disease symptoms. Additionally, mutations in non-coding regulatory regions, which are not detected by this test, may also cause inactivation of alpha globin genes. This test is intended for pre/post-conception carrier screening and is not intended for diagnostic testing.

Gene(s)

HBA1 HBA2

MIM

613978 236750

Methodology

Billing

CPT Code(s)
81257 x 1

Ordering

Test Code
6005

Additional Test Codes
Please call for Pricing

Turnaround Time
Typically within 2 weeks from receipt of a sample in the laboratory.

Specimens
Whole blood: purple-top (EDTA) tube, minimum of 3 ml
Genomic DNA: minimum of 3 µg (at a concentration of at least 30 ng/µl)

Shipping
Ship all specimen types at room temperature by overnight courier. Do not freeze.

The American Medical Association (AMA) Current Procedural Terminology (CPT) codes published by HNL Lab Medicine are guidelines and are intended for informational purposes only. CPT coding is the exclusive responsibility of the billing entity. HNL Lab Medicine strongly recommends confirmation of CPT codes with third-party payors and/or the AMA. We assume no responsibility for billing errors due to reliance upon CPT codes provided by HNL Lab Medicine.

News

October 28, 2022

Non-Hodgkin Lymphoma FISH Panel Now Available

B-cell lymphoma is a large group of heterogenous disorders and comprises a majority of non-Hodgkin lymphomas.
Read More
October 20, 2022

Genetic testing for Familial Transthyretin Amyloidosis (TTR) NOW AVAILABLE In-House

Hereditary amyloidosis is a life-threatening disorder that can lead to peripheral neuropathy and heart failure.
Read More
August 08, 2022

Familial hypercholesterolemia (FH)

Familial hypercholesterolemia (FH) is a genetic disorder that increases the likelihood of having coronary heart disease at a younger age. Learn about how to determine if you have hypercholesterolemia and what actions you can take to create better outcomes!

Read More
April 11, 2022

Genome Sequencing: A Vital Tool Used in Identifying and Tracking New COVID-19 Variants

Genome sequencing is reading or decoding the complete genetic information i.e. “Genome” of an organism that is encrypted in the form of a very long string called DNA made up of 4 letters, A, T, G, and C. The genome of an organism essentially determines their physical characteristics and ...
Read More
March 03, 2022

The Effect of Genetics on Individual Heart Health: Early Identification of FH Variations to Optimize Treatment

Test must be ordered by a Physician.

Familial hypercholesterolemia (FH) is a genetic disorder that is characterized by abnormally high blood levels of low-density lipoprotein (LDL) cholesterol, sometimes referred to as "bad cholesterol". This condition affects an estimated 1 in 250 people, and increases the likelihood of developing cardiovascular disease. In fact, FH is estimated to be the cause of 2-3% of heart attacks in individuals younger than age 60.

Read More