Folic acid-responsive neurological diseases in Japan

Folic acid (folate) levels were measured in the serum of patients with vari ous neurological diseases in Japan. Thirty-six patients showed decreased se rum folate levels among 343 consecutive neurological patients (10.5%). Fola te administration (15 mg/d) to folate-deficient patients improved neurologi cal symptoms in 24 of 36 cases (67%). Serum folate levels were significantl y lower in female than in male folate-deficient patients. Folate-deficient patients showed predominantly axonal neuropathy, which responded to folate supplementation more markedly. Male patients more frequently exhibited neur opathy, especially demyelinating and motor-dominant neuropathy. than female s. Anemia was correlated with male sex and low serum folate levels. Male pa tients were more responsive than females to folate treatment. More male pat ients had taken excess alcohol or received gastrectomies than females. Neur ological symptoms were more frequently improved by folate supplementation i n patients with neuropathy than exclusive encephalopathy. Serum folate leve ls were lower in patients with encephalopathy, especially those with dement ia, while folate therapy was more effective in neurological patients withou t dementia. Dysgeusia and anemia improved in all patients after folate admi nistration. Neurological patients with malabsorption or treated with contin uous drip infusion were resistant to folate therapy. Since folate-responsiv e neuroencepahlopathies are not rare among patients with neurological disea ses in Japan, the serum folate level would serve as a valuable indicator fo r folate supplement therapy.