title: Unrecognized cobalamin-responsive neuropsychiatric disorders.
abstract: Neuropsychiatric disorders due to cobalamin deficiency occur in the absence of anemia or significant macrocytosis and may be overlooked because usual clinical laboratory tests are unreliable for diagnosis of cobalamin deficiency. Serum methylmalonic acid and homocysteine levels appear to be sensitive and accurate markers of cobalamin deficiency.
mesh_terms: D006801:Humans; D009497:Neurotic Disorders / Q000209:etiology*; D014806:Vitamin B 12 Deficiency / Q000150:complications*