Glycine is a chemical that transmits messages from one nerve cell to another. Most receptors for glycine are found at connections between nerve cells in the spinal cord and brainstem (See Figure below). These receptors also contain a pore that allows chloride molecules to pass into the cell. Some glycine receptor types bind to a protein called synphilin-1, which is found inside nerve cells. Synphilin-1 is linked to two other proteins, alpha-synuclein and parkin. Changes in the genes that produce these proteins referred to as mutations occur in a small number of families with familial/inherited forms of Parkinson’s.