Tetrahydrobiopterin deficiencies •DHPR deficiency: Developmental delay, epilepsy, microcephaly, Parkinsonism, cerebral atrophy and basal ganglia calcifications. •AR GTPCH deficiency: Developmental delay, epilepsy, microcephaly, truncal hypotonia, limb hypertonia. •PTPS deficiency: Developmental delay, epilepsy, microcephaly, Parkinsonian dystonia, lethargy, autonomic dysfunction. Tyrosine Hydroxylase deficiency feat: dystonia, postural tremor, developmental and motor delay, limb rigidity, hypokinesia, ptosis and oculogyric crisis. Here, AR is linked to microcephaly.