An infant with cerebral folate deficiency has autoantibodies directed against membrane-bound folate receptors in epithelial cells of the choroids plexus. These block the receptors so that folate cannot be transported into the central nervous system.


Onset of symptoms: usually from 4 to 6 months of age


Clinical findings:

(1) marked irritability with insomnia

(2) psychomotor retardation, neurodevelopmental regression

(3) cerebellar ataxia

(4) ascending pyramidal tract signs affecting the legs

(5) decelerating head growth

(6) choreoathetosis, ballismus and other dyskinesias

(7) hypotonia

(8) seizures (variable)

(9) response to oral folinic acid therapy


Complications that develop during childhood:

(1) optic atrophy with blindness

(2) hearing loss


Laboratory findings:

(1) normal folate levels in serum

(2) normal folate levels within erythrocytes

(3) low levels of 5-methyltetrahydrofolate (5MTHF) in the cerebrospinal fluid

(4) presence of serum autoantibodies against the folate receptor


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