[Convulsions and encephalopathy as initial manifestations of cyanocobalamin deficiency, without hematologic changes]

A case of deficiency of cobalamin coenzyme synthesis whose first manifestation was encephalopathy with seizures and no trace of megaloblastic anemia is presented. After a while, signs of posterior cord and polyneural disfunction were detected. We highlight the rareness of the case and the difficulty of the diagnosis because of the discrepancy between neurologic and hematologic signs, as well as the need for early diagnosis which is an important factor for observing therapeutic response.