Is there a genetic test for alpha thalassemia?
DNA testing. In a pregnant woman, the baby is diagnosed using CVS (chorionic villus sampling) or amniocentesis. A DNA test is needed to make a diagnosis of alpha thalassemia.
What is alpha globin common mutation analysis?
Alpha-Globin Common Mutation Analysis – Alpha Thalassemia is a common hereditary trait and disease among individuals of Asian heritage. Disease ranges in severity from mild abnormalities of erythrocytic indices to severe anemia. Genetic counseling may be advised for some patients.
How is HbH disease diagnosed?
HbH disease should be considered in infants or children with mild-to-moderate microcytic hypochromic hemolytic anemia and hepatosplenomegaly. Heinz bodies can be detected on blood smears after cresyl blue staining. Hb biochemical analysis reveals the presence of HbH (5-30%). Diagnosis is confirmed by genetic testing.
What is the genetic test for thalassemia?
Targeted deletion analysis for common HBA1 and HBA2 variants is recommended as a first genetic test for α thalassemia, followed by sequencing.
What is alpha thalassemia DNA analysis?
More than 95% of recognized α-thalassemia involves deletion of one or both α-globin genes from chromosome 16p13. 3. DNA analysis of the α-globin region (HBA1/HBA2, OMIM 141800/141850, 16pter-16p13. 3) is performed by targeting 28 different sequences using multiplex ligation-dependent probe amplification (MLPA).
What is alpha globin gene?
Alpha-globin is a component of both fetal hemoglobin, which is active only before birth and in the newborn period, and adult hemoglobin, which is active throughout the rest of life. Each of the four protein subunits of hemoglobin carries an iron-containing molecule called heme.
What are the symptoms of alpha thalassemia?
What Are the Signs & Symptoms of Hemoglobin H Disease or Alpha Thalassemia Major?
- extreme tiredness.
- pale skin.
- shortness of breath.
- a fast heartbeat.
- yellow skin and eyes (jaundice)
- moodiness or irritability.
- slow growth.
- change in the shape of bones in the face and head.
Is HbH disease serious?
Hemoglobin H disease. This type causes moderate to severe symptoms. These include lack of energy (fatigue) and exercise intolerance. You may also have an enlarged liver or spleen, yellowish skin, and leg ulcers. You have a greater risk of having a child with the most severe type, alpha thalassemia major.
How can you tell the difference between iron deficiency and thalassemia?
Distinguishing Iron Deficiency Anemia From Thalassemia Trait The first difference is in the red blood cell count (labeled RBC). In iron deficiency, this value is low because the bone marrow is unable to manufacture red blood cells. In thalassemia trait, RBC is normal to elevated.
How is thalassemia tested during pregnancy?
Prenatal diagnosis of β thalassemia using CVS can be carried out at 9–11 weeks. Amniocentesis can be carried out in 14–18 weeks of pregnancy; fetal blood testing can be done in 18–20 weeks of pregnancy. Techniques include site specific restriction endonuclease analysis, PCR, and oligonucleotide probes.
Why is alpha-globin important?
Within cells, the erythroid-specific molecular chaperone α hemoglobin stabilizing protein specifically binds to multiple forms of α-globin (apo, ferrous, and ferric) and stabilizes free α-chains by promoting protein folding and resistance to protease digestion.
Does the presence of α gene triplication in heterozygosis affect hemoglobin synthesis?
The presence of α gene triplication in heterozygosis has no effect on the synthesis of α globin chains in hemoglobin and subjects are usually clinically asymptomatic.
How many alpha globin genes are there in thalassemia?
Four alpha-globin genes are normally present (2 on each chromosome 16). One, 2, 3, or 4 alpha-globin genes may be deleted or, less commonly, contain variants. Deletions account for approximately 90% of disease-causing alleles in alpha thalassemia.
What causes α gene triplication (ααα anti 3)?
In addition, the patient had α gene triplication (ααα anti 3.7 /αα) caused by double heterozygosity for a 3.7 kb fragment that contained only the hemoglobin alpha globin gene-2 gene. This finding led to screening and follow up in first-degree relatives, twin brothers and a sister and parents to provide them with appropriate genetic counseling.
Where are the duplicated human alpha globin genes found?
The duplicated human alpha globin genes lie close together in cellular DNA. Proc Natl Acad Sci U S A. 1978 Dec;75(12):5950–5954. [PMC free article][PubMed] [Google Scholar] Embury SH, Lebo RV, Dozy AM, Kan YW. Organization of the alpha-globin genes in the Chinese alpha-thalassemia syndromes. J Clin Invest. 1979 Jun;63(6):1307–1310.