Neurologic disorders responsive to folic acid therapy.

Six women aged 31 to 70 years had folate deficiency and neuropsychiatric disorders. The three with acquired folate deficiency were depressed and had permanent muscular and intellectual fatigue, mild symptoms of restless legs, depressed ankle jerks, diminution of vibration sensation in the legs, stocking-type hypoesthesia and long-lasting constipation; D-xylos absorption was abnormal. The bone marrow was megaloblastic in only one patient, and she and one other had atrophy of the jejunal mucosa. The third was a vegan. All three recovered after folic acid therapy. The other three were members of a family with the restless legs syndrome, fatigability and diffuse muscular pain. One also had subacute combined degeneration of the spinal cord and kidney disease but no megaloblastosis; she improved spectacularly after receiving large daily doses of folic acid. The other two also had minor neurologic signs, controlled with 5 to 10 mg of folic acid daily. Unrecognized and treatable folate deficiency (with low serum folic acid values but normal erythrocyte folate values) may be the basis of a well defined syndrome of neurologic, psychiatric and gastroenterologic disorders, and the restless legs syndrome may represent the main clinical expression of acquired and familial (or inborn) folate deficiency in adults.