Thalassemia minor presenting with vitamin B 12 deficiency, paraparesis, and microcytosis

Abstract

Vitamin B 12 is essential for proper neurological functioning, and its deficiency may cause a wide range of neuropsychiatric and hematological manifestations. We report a case of a previously healthy 32-year-old female who was admitted to our hospital with sudden onset of bilateral lower limb paraparesis and loss of sensation. The serum level of vitamin B 12 was mildly decreased with high methylmalonic acid and homocysteine levels. However, her complete blood count showed no evidence of anemia or macrocytosis; instead, her mean corpuscular volume was low. Hemoglobin electrophoresis showed thalassemia trait, and that probably masked the megaloblastic features of vitamin B 12 deficiency. She responded fully to vitamin B 12 replacement therapy.