Disappearance of cerebral cortical atrophy following replacement therapy with vitamin B12 in an infant

Abstract

Vitamin B12 (cobalamin) deficiency during infancy is seen most commonly in exclusively breast-fed infants born to mothers with inadequate vitamin B12 stores. In addition to megaoblastic anemia, physical, social and neuromotor retardation may be seen in affected patients. In severe cases, thrombocytopenia and neutropenia may accompany anemia mimicking leukemia or aplastic anemia. Patients may rarely develop cerebral cortical atrophy evident on neuroimaging. In this article, a 12-month-old female infant with psychomotor developmental retardation who was referred to our hospital with the initial diagnosis of leukemia due to the finding of pancytopenia is presented. Further investigations revealed severe nutritional vitamin B12 deficiency in this case. Cranial magnetic resonance imaging (MRI) showed cerebral cortical atrophy. Replacement therapy with vitamin B12 resulted in marked improvement of psychomotor status, and cranial MRI performed 7 months following the diagnosis and treatment initiation revealed resolution of cortical atrophy.