In particular, a specific immunohistochemical protocol designed to evaluate the neuronal expression of the tyrosine hydroxylase (TH), a marker of catecholaminergic neurons [21], and the dopamine transporter (DAT), a membrane-bound protein specifically expressed in the DA cells [22,23], was applied to 36 SIDS cases and 26 age-matched controls. The gene discussed is SLC6A3; the disease is sudden infant death syndrome.