Table 5: Serine synthesis defects.

DisorderEpilepsy and neuroimaging featuresResponse to treatment with
L-serine and glycine

3-Phosphoglycerate dehydrogenase deficiencyInfantile phenotype:Infantile phenotype:
(i) intractable seizures(i) Seizure control or significantly lowered frequency
(ii) MRI: hypomyelination and delayed myelination  (ii) Increased white matter volume
Juvenile phenotype: Juvenile phenotype:
(i) absence seizures(i) Seizure control
(ii) MRI: no abnormalities(ii) Prevention of neurological abnormalities
Phosphoserine Aminotransferase deficiencySymptomatic patient:Symptomatic patient:
(i) intractable seizures(i) No clinical response to treatment 
(ii) MRI: generalized atrophy, including cerebellar vermis and pons, white matter abnormalities
Presymptomatic patient:Presymptomatic patient:
(i) MRI: no abnormalities(i) Prevention of all neurological abnormalities
Phosphoserine phosphatase deficiencySingle case, details not reportedNot reported

Adapted from Pearl [2].