A rare inborn error of metabolism comprising 3-phosphoglycerate dehydrogenase deficiency, 3-phosphoserine phosphatase deficiency and phosphoserine aminotransferase deficiency. The disease has a phenotypic spectrum ranging from congenital microcephaly, psychomotor retardation and intractable seizures in the infantile forms to milder juvenile forms with moderate developmental delay and intellectual disability. [from
SNOMEDCT_US]