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.

Does thalassemia cause hemolysis?

The thalassemias (named from the Greek word for sea, thalassa1) are a group of inherited autosomal recessive hematologic disorders2 that cause hemolytic anemia because of the decreased or absent synthesis of a globin chain. Imbalances of globin chains cause hemolysis and impair erythropoiesis.

What is HbH blood test?

Hemoglobin H disease (HbH) is a form of alpha thalassemia in which moderately severe anemia develops due to reduced formation of alpha globin chains. In this condition, as in the other forms of thalassemia, there is an imbalance of globin chains needed to form hemoglobin.

What is the defect usually found in HbH disease?

Hemoglobin H disease, or α-thalassemia intermedia, occurs as a result of deletion mutations of three of four α-globin genes, causing a deficiency of the α-globin chains of hemoglobin and an excess production of β-globin chains.

What are HbH inclusion bodies?

Hemoglobin H bodies are seen as faint blue inclusions. They appear to be on the outside of the cell, resembling sugar on a gumdrop; however, in actuality these inclusions are located just inside the red blood cell’s membrane and push outward.

What are the inclusion bodies in HBH disease composed of?

Heinz bodies (also referred to as “Heinz-Ehrlich bodies”) are inclusions within red blood cells composed of denatured hemoglobin. They are not visible with routine blood staining techniques, but can be seen with supravital staining.

Why is hba2 increased in beta thalassemia?

Hb A2 is increased in beta thalassemia because the relative lack of beta globin allows more delta chains to be incorporated into hemoglobin. Beta thalassemia is caused by mutations in the beta globin gene locus on chromosome 11.

What is Mentzer index in blood test?

The Mentzer index, described in 1973 by William C. Mentzer, is the MCV divided by the RBC count. It is said to be helpful in differentiating iron deficiency anemia from beta thalassemia. The index is calculated from the results of a complete blood count.

What are the 4 types of alpha thalassemia?

There are 4 types of alpha thalassemia:

• Alpha thalassemia silent carrier. One gene is missing or damaged, and the other 3 are normal. Blood tests are usually normal.
• Alpha thalassemia carrier. Two genes are missing.
• Hemoglobin H disease. Three genes are missing.
• Alpha thalassemia major. All 4 genes are missing.

What are the red blood cell inclusion bodies that stain Supravitally?

4. Other RBC inclusions that stain supravitally include Heinz, Howell-Jolly, and Pappenheimer bodies (Table 16.3). Heinz bodies are precipitated hemoglobin, usually appear round or oval, and tend to adhere to the cell membrane (Figure 11.12).