Thalassemia
Thalassemia is the name of a group of genetic blood disorders passed down through families (inherited) in which the body makes an abnormal form of hemoglobin. Hemoglobin is the oxygen carrying protein in red blood cells and consist of two different proteins - Alpha Globin & Beta Globin. If the body doesn't produce enough of the two proteins, RBC do not form properly and cannot carry sufficient oxygen. The result is anemia. Anemia is a condition in which body doesn’t have enough normal & healthy red blood cells. Thalassemia occurs when there’s an abnormality or mutation in one of the genes involved in hemoglobin production. Thalassemics inherit this genetic defect from their parents. Thalassemia is inherited, meaning that at least one of the parents must be a carrier of the disease. It’s caused by either a genetic mutation or a deletion of certain key gene fragments.
Thalassemia Minor is a less serious form of the disorder. There are two main forms of Thalassemia that are more serious. In Alpha Thalassemia, at least one of the alpha globin genes has a mutation or abnormality. In beta thalassemia, the beta globin genes are affected.
• Alpha Thalassemia: People whose hemoglobin doesn't produce enough alpha globin have Alpha Thalassemia. In other words, in Alpha Thalassemia, at least one of the alpha globin genes has a mutation or abnormality. Alpha Thalassemia occur most often in people from Southeast Asia, the Middle East, China, and in those of African descent.
• Beta Thalassemia: People whose hemoglobin doesn't produce enough beta globin have Beta Thalassemia. In Beta Thalassemia, the beta globin genes are affected. Beta Thalassemia occur most often in people of Mediterranean origin. To a lesser extent, Chinese, other Asians, and African Americans can be affected. Beta Thalassemia is prevalent in almost every ethnic group of our country i.e., Gujaratis, Sindhis, Punjabis, Marathas, Jains, Baniyas, Bora Muslims and tribal. Various studies revealed that carrier rate in our country varies from 0% – 17% of population with average 3% in general population.
There are 7 types of Alpha Thalassemia that range from mild to severe in their effect on the body.
• Silent Carrier State: This causes no health problems because the deficiency of alpha protein is so small that the hemoglobin functions normally. It is called 'Silent Carrier' because of its difficulty to detect. Silent Carrier is diagnosed when an apparently normal individual has a child with Alpha Thalassemia Trait.
• Hemoglobin Constant Spring: This is an unusual form of Silent Carrier state that is caused by a mutation of the alpha globin. It is called Constant Spring after the region of Jamaica in which it was discovered. As in silent carrier state, an individual with the condition usually experiences no related health problems.
• Alpha Thalassemia Trait: In this condition, the lack of alpha globin is somewhat greater. Patients suffering from Alpha Thalassemia Trait have smaller RBC & a mild anemia, although many patients don't experience any symptoms.
• Hemoglobin H Disease: In this condition, lack of alpha globin is great enough to cause severe anemia and serious health problems such as enlarged spleen, bone deformities & fatigue. It is named for the abnormal Hemoglobin H, created by the remaining beta globin, that destroys RBCs.
• Hemoglobin H-Constant Spring: This condition is more severe than Hemoglobin H disease. Individuals with this condition tend to have a more severe anemia and suffer more frequently from enlargement of spleen and viral infections.
• Homozygous Constant Spring: This condition is a variation of Hemoglobin H-Constant Spring generally less severe than Hemoglobin H-Constant Spring and more similar to Hemoglobin H Disease.
• Alpha Thalassemia Major: In this condition, there are no alpha genes in the individual's DNA, which causes the gamma globins produce by the fetus to form an abnormal called Hemoglobin Brats. Most individuals with this condition die before or shortly after birth. In some extremely rare cases where the condition is discovered before birth, in utero blood transfusion have allowed the birth of children when hydrops fetalis who then require lifelong blood transfusion and medical care.
There are 3 types of Beta Thalassemia that range from mild to severe in their effect on the body.
• Thalassemia Minor or Thalassemia Trait: In this condition, lack of beta globin is not great enough to cause problems in the normal functioning of the Hemoglobin. A person with this condition simply carries the genetic trait for Thalassemia and will usually experience no health problems other than a possible mild anemia.
• Thalassemia Intermedia: In this condition, lack of beta globin in the hemoglobin is great enough to cause a moderately severe anemia and significant health problems, including bone deformities & enlargement of the spleen. Patients with Thalassemia Intermedia require blood transfusion to improve their quality of life but not in order to survive.
• Thalassemia Major: This is the most severe form of Beta Thalassemia in which the complete lack of beta globin in the Hemoglobin causes a life-threatening anemia that requires regular blood transfusion and extensive ongoing medical care. Theses extensive, lifelong blood transfusion lead to iron-overload which must be treated with chelation therapy to prevent early death from organ failure.

Normal RBC & Thalassemic RBC

In case Mother is unaffected & Father is a carrier,
the risk for child to
Have Thalassemia: 0% | Become a Carrier: 50%

In case both the parents are a carrier,
the risk for child to
Have Thalassemia: 25% | Become a Carrier: 50%

In case mother is a Thalassemia Major & Father is a carrier,
the risk for child to
Have Thalassemia: 50% | Become a Carrier: 50%

In case both the parents are Thalassemia Major,
the risk for child to
Have Thalassemia: 100%

Inheritance pattern of Alpha Thalassemia

Inheritance pattern of Beta Thalassemia