Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) phosphoglycerate dehydrogenase deficiency ?
    ### Response:
    Phosphoglycerate dehydrogenase deficiency is a condition characterized by an unusually small head size (microcephaly); impaired development of physical reactions, movements, and speech (psychomotor retardation); and recurrent seizures (epilepsy). Different types of phosphoglycerate dehydrogenase deficiency have been described; they are distinguished by their severity and the age at which symptoms first begin.
    