The extent of hyperechogenic substantia nigra differed between cases with genetic causes and others, but these differences were small.
Transcranial sonography of the midbrain reveals hyperechogenic substantia nigra in more than 90% of patients with idiopathic Parkinson disease (PD) but in only in about 10% of healthy controls. Because the size of hyperechogenic areas does not appear to change during PD, this finding has been suggested as a PD biomarker of trait but not of state. Monogenic forms of PD are often clinically indistinguishable from idiopathic, nongenetic PD and account for about 2% to 3% of cases.
To investigate whether hyperechogenic substantia nigra is also characteristic of genetic PD, these authors performed transcranial sonography on 14 patients with one of the five monogenic forms (SNCA/PARK1; parkin/PARK2; PINK1/PARK6; DJ-1/PARK7; or LRRK2/PARK8) and on 2…