SNCA and Parkinson disease: The putamen ASI for bi-allelic Parkin (median 0.69 [0.2–1.0], p = 0.2), PINK1 (median 1.05 [0.9–1.4], p = 0.14) and SNCA (median 1.05 [0.92–1.22], p = 0.30) mutation associated PD did not differ from control values (median 0.89 [0.82–0.86]).