**Question:** In β-thalassemia, there is

A. deficiency of β-globin chains production
B. decreased hemoglobin A2 levels
C. increased α-globin chains production
D. reduced red blood cell survival

**Correct Answer:** A. deficiency of β-globin chains production

**Core Concept:**
Thalassemias are a group of inherited blood disorders characterized by reduced or absent production of globin chains within red blood cells (RBCs). There are two main types: α-thalassemia and β-thalassemia. In α-thalassemia, there is a deficiency of α-globin chains production, while in β-thalassemia, there is a deficiency of β-globin chains production.

**Why the Correct Answer is Right:**
In β-thalassemia, the correct answer (A) is due to the reduced production of β-globin chains. This results in an imbalance between α-globin and β-globin chains, leading to abnormal RBCs with increased membrane fragility and reduced half-life.

**Why Each Wrong Option is Incorrect:**

Option B (decreased hemoglobin A2 levels) is incorrect because hemoglobin A2 is a small fraction of total hemoglobin (Hb) which is composed of α2 and δ2 globin chains. In β-thalassemia, the main issue is with β-globin chains, not Hb A2 levels.

Option C (increased α-globin chains production) is incorrect because, in contrast to α-thalassemia where there is reduced α-globin production, in β-thalassemia, the issue is with reduced β-globin chains production.

Option D (reduced red blood cell survival) is partially correct but not the main cause. The reduced red blood cell survival is a consequence of the reduced β-globin chains production, but the primary issue is with the reduced β-globin chains production.

**Clinical Pearl:**

Understanding the distinction between α-thalassemia and β-thalassemia is crucial for proper diagnosis and management. In α-thalassemia, the issue is with the α-globin chains production, while in β-thalassemia, the issue is with the β-globin chains production. This distinction helps in differentiating between the two types of thalassemias and determining the required treatment and management strategies.