SNP Shot: Genomic Insights

Beta thalassemia is a blood disorder characterized by reduced production of hemoglobin. Hemoglobin, found in red blood cells, is responsible for carrying oxygen to all the body's cells.

Individuals with beta thalassemia have lower-than-normal hemoglobin levels, leading to reduced oxygen delivery throughout the body. This results in a shortage of red blood cells (anemia), which can cause symptoms like pale skin, weakness, and fatigue, and can lead to more serious health issues. Furthermore, those with beta thalassemia face a higher risk of developing blood clots.

Beta thalassemia is broadly categorized into two types based on symptom severity: thalassemia major (also called transfusion-dependent thalassemia or Cooley's anemia) and thalassemia intermedia (a non-transfusion-dependent form). Thalassemia major is the more severe of the two.

Thalassemia major symptoms typically manifest within the first two years of life. Affected children develop severe, life-threatening anemia, experience failure to thrive (poor weight gain and growth), and may exhibit jaundice (yellowing of the skin and eyes). They may also have enlarged spleens, livers, and hearts, and bone deformities. In some adolescents with thalassemia major, puberty is delayed.

Many individuals with thalassemia major require frequent blood transfusions to maintain their red blood cell count. However, repeated transfusions introduce excess iron into the body, which can accumulate and cause complications affecting the liver, heart, and hormone production.

Thalassemia intermedia is less severe than thalassemia major. Its symptoms appear in early childhood or later. Individuals with thalassemia intermedia experience mild to moderate anemia and may also have slow growth, bone abnormalities, and an increased risk of blood clots.

Inheritance:

Thalassemia major and thalassemia intermedia are typically inherited in an autosomal recessive manner. This means that an individual must inherit a mutated copy of the HBB gene from *both* parents. The parents, who each carry one copy of the mutated gene, usually don't show symptoms. However, some individuals with just one mutated HBB gene may develop mild anemia, a condition known as thalassemia minor. In a small number of families, beta thalassemia can be inherited in an autosomal dominant pattern, where a single mutated copy of the HBB gene is enough to cause the condition's signs and symptoms.