Parkinson disease (PD) is one of the most common neurodegenerative disorders with major clinical features of bradykinesia, rigidity, resting tremor, and postural instability. At least thirteen gene loci responsible for PD or parkinsonism have been found and nine causative genes have been identified. Recently, Asn56Ser or Asn457Thr mutations in the Grb10-Interacting GYF Protein-2 gene (GIGYF2) were found to occur in about 2.4% familial PD Italian and French patients. We conducted genetic examination of Asn56Ser or Asn457Thr mutations, but none was found in 310 PD patients from North America. We did identify a non-disease-associated polymorphism Pro460Thr. Our results suggest that the GIGYF2 Asn56Ser and Asn457Thr mutations are a rare cause of PD in North American Caucasian population.