Adult-onset cerebral folate deficiency.

OBJECTIVE To report new manifestations of cerebral folate deficiency, a rare metabolic autoimmune syndrome,in an adult. DESIGN Case report. SETTING University teaching hospital. PATIENT A 58-year-old woman with progressive memory loss and myoclonus presented for medical attention. Results of cerebral spinal fluid analysis showed low levels of tetrahydrobiopterin and 5-methyltetrahydrofolate. The patient's serum folate level was normal. Serum contained folate receptor 1 blocking and binding antibodies. RESULTS The patient was treated successfully with folinic acid supplementation, and after 6 months of treatment,clinical symptoms had resolved. CONCLUSIONS To our knowledge, we report the first case of adult-onset cerebral folate deficiency. Furthermore, this condition could represent a treatable form of early-onset dementia.