DNA repair — MCQs

Question 1: A software engineer presents to the OPD with 'complaints of easy fatigability. He reports sitting in front of a computer for 12-14 hours a day consuming junk food, and eating few fruits and vegetables. CBC results show hemoglobin (Hb) concentration of $7 \mathrm{gm} \%$ and MCV of 120 fL . What is the most likely cause of anemia?

• A. Cyanocobalamin deficiency
• B. Acute blood loss
• C. Sideroblastic anemia
• D. Folate deficiency (Correct Answer)
• E. Iron deficiency anemia

Explanation: ***Folate deficiency*** - A **macrocytic anemia** with an **MCV of 120 fL** is characteristic of folate deficiency, as folate is vital for **DNA synthesis** in red blood cell production. - The patient's diet of **junk food** and few fruits/vegetables suggests poor nutritional intake, as folate is abundant in leafy greens and fresh produce. *Cyanocobalamin deficiency* - While also causing **macrocytic anemia** with high MCV, cyanocobalamin (Vitamin B12) deficiency often presents with **neurological symptoms** (e.g., neuropathy, cognitive changes) which are not mentioned. - Dietary sources of B12 are primarily **animal products**, and while junk food is poor, a strict vegetarian/vegan diet is a stronger indicator of B12 deficiency. *Acute blood loss* - Acute blood loss typically causes **normocytic, normochromic anemia**, characterized by a normal MCV in the initial stages. - While severe blood loss can lead to fatigue, the **elevated MCV** of 120 fL makes this diagnosis unlikely unless there's a pre-existing macrocytic condition. *Sideroblastic anemia* - Sideroblastic anemia can be **microcytic, normocytic, or macrocytic**, but it is primarily characterized by the presence of **ring sideroblasts** in the bone marrow and iron overload. - It's often associated with **alcoholism, lead poisoning, or myelodysplastic syndromes**, and the typical features of the patient's diet and MCV do not point towards this condition. *Iron deficiency anemia* - Iron deficiency anemia presents with **microcytic, hypochromic anemia** with a **low MCV** (typically <80 fL), not macrocytic anemia. - While iron deficiency is the most common cause of anemia worldwide and can result from poor diet, the **elevated MCV of 120 fL** clearly excludes this diagnosis.