Phosphoserine aminotransferase deficiency OMIM:610992 PSAT deficiency orphanet ICD10:E72.8 Phosphoserine aminotransferase deficiency is an extremely rare form of serine deficiency syndrome (see this term) characterized clinically in the two reported cases to date by acquired microcephaly, psychomotor retardation, intractable seizures and hypertonia. Disorder of serine or glycine metabolism