From the Guidelines
Yes, thalassemia minor does cause a mild form of anemia. People with thalassemia minor have smaller red blood cells and less hemoglobin than normal, resulting in mild anemia that is typically asymptomatic. This condition occurs when a person inherits one defective gene for beta or alpha thalassemia from one parent. The anemia in thalassemia minor is microcytic (small red blood cells) and hypochromic (less color in the cells due to reduced hemoglobin).
Key Characteristics of Thalassemia Minor
- Microcytic anemia: characterized by small red blood cells
- Hypochromic anemia: characterized by less color in the cells due to reduced hemoglobin
- Typically asymptomatic
- Does not improve with iron supplements, and taking unnecessary iron can actually be harmful
Diagnosis and Considerations
According to the Centers for Disease Control and Prevention 1, if after 4 weeks the anemia does not respond to iron treatment despite compliance with the iron supplementation regimen and the absence of acute illness, further evaluation of the anemia is necessary using other laboratory tests, including MCV, RDW, and serum ferritin concentration. In women of African, Mediterranean, or Southeast Asian ancestry, mild anemia unresponsive to iron therapy may be due to thalassemia minor or sickle cell trait. Most people with thalassemia minor lead normal, healthy lives without treatment and may only discover their condition during routine blood tests. However, genetic counseling is important for those with thalassemia minor who are planning to have children, as there is a risk of having a child with the more serious thalassemia major if both parents carry the trait.
From the Research
Thalassemia Minor and Anemia
- Thalassemia minor, also known as beta-thalassemia trait, is a mild form of thalassemia that can cause microcytic hypochromic anemia 2, 3, 4.
- Microcytic hypochromic anemia is characterized by small, pale red blood cells and can be caused by various factors, including iron deficiency, thalassemia, and other conditions 5, 4.
- Thalassemia minor can be differentiated from iron deficiency anemia using various laboratory tests, including red blood cell indices, such as mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and red blood cell count (RBC) 2, 3, 4.
Diagnostic Criteria
- A study published in 2023 found that low hemoglobin density (LHD) and microcytic anemia factor (MAF) can be used to differentiate between thalassemia trait and iron deficiency anemia 2.
- Another study published in 2015 found that the microcytic to hypochromic RBC ratio can be used as a discriminant index in microcytic anemia to distinguish thalassemia from iron deficiency 4.
- The molecular basis of α-thalassemia, a related condition, involves deletions and point mutations affecting the expression of one or more of the duplicated α-genes, leading to decreased expression of α-globin genes 6.
Clinical Implications
- Thalassemia minor can cause anemia, but it is typically mild and may not require treatment 3, 4.
- Iron deficiency anemia, on the other hand, requires treatment with iron supplements to replenish iron stores and correct the anemia 5.
- Accurate diagnosis of thalassemia minor and iron deficiency anemia is crucial to provide appropriate management and treatment 2, 5, 3, 4.