Q&A Medicine>>>>>Hematology and Oncology
Question 9#

A 24-year-old woman with a history of asthma presents with fatigue. She does not have a family history as she was adopted in Albania and came to the United States when she was born. The patient reports regular menstrual cycles and denies taking any medications. Laboratory studies reveal the following:

• Leukocyte count   8,500/mm³
• Hemoglobin   9.8 g/dL
• Hematocrit   30%
• Mean corpuscular volume   70 fL
• Mean corpuscular hemoglobin concentration   27%
• Platelets   290,000/mm³

The patient is treated with iron supplementation and returns 8 weeks later without improvement in laboratory values.

Which of the following is the likely cause of this patient’s condition?

A. Folic acid deficiency
B. Red blood cell enzyme deficiency
C. Anti-RBC antibodies
D. Point mutation in one of the β-hemoglobin genes

Correct Answer is D

Comment:

Point mutation in one of the b-hemoglobin genes. The patient in this question is presenting with microcytic anemia that is not responding to treatment with iron. Given her Mediterranean origin, she likely has β-thalassemia. People typically have two functional copies of the β-hemoglobin gene, but those with β-thalassemia have a point mutation in one or both of these genes (classified as minor and major, respectively). This generates reduced hemoglobin production creating a hypochromic microcytic anemia. β-thalassemia major results in severe and life-threatening anemia and the need for many blood transfusions, so this patient likely has the minor form. (A) Folic acid deficiency results in macrocytic megaloblastic anemia with hypersegmented neutrophils on peripheral blood smear. (B, C) These conditions cause a normocytic anemia, but this patient has a microcytic anemia (MCV <80 fL).