5-methyltetrahydrofolate (CSF)

Cerebral folate deficiency (CFD) is a neurological condition associated with low levels of 5MTHF in the CSF with normal 5MTHF in the peripheral circulation. In CFD the age of onset for symptoms is 4-6 months when there is deceleration of head growth, irritability and insomnia. After 6 months there is a delay in neurodevelopmental milestones including psychomotor retardation and hypotonia with poor postural control. After six years of age visual disorders may also develop. Some of the children also develop spasticity, speech difficulties and epilepsy. There have been a number of suggested causes for CFD including decreased transport across the blood-brain barrier. The suggested mechanisms for the decreased transport across the blood-brain barrier include blocking of folate receptor 1 by autoantibodies and mutations in the FOLR1 gene. A possible mechanism of autoantibody production can be exposure to soluble folate receptors from milk because soluble folate receptors in cow’s milk have 90 % homology to the human receptor. Treatment of CFD with folinic acid over a long period can significantly improve clinical symptoms in patients with CFD.