Screening of previously known amino acid substitutions in the synphilin-1 gene, identified the C1861>T (R621C) substitution in four patients (chromosomes n = 600) and 10 control subjects (chromosomes n = 824), whereas the G2125>C (E706Q) substitution was detected in one patient and four control subject, suggesting both these substitutions are not associated with susceptibility to PD. Here, SNCAIP is linked to Parkinson disease.