Snca has been found in cerebrospinal fluid (CSF) and plasma and its concentration in these fluids has been suggested as a possible biomarker for PD (Parnetti et al., 2013), even though there are substantial discrepancies between the results reported in different studies (Lee et al., 2006; Li et al., 2007; Duran et al., 2010; Shi et al., 2010; Mollenhauer et al., 2011; Park et al., 2011; Foulds et al., 2012; Wennstrom et al., 2013). The gene discussed is SNCA; the disease is Parkinson disease.