Transcranial sonography in pantothenate kinase-associated neurodegeneration

After it was reported that increased tissue iron concentrations were associated with increased echogenicity of the substantia nigra (SN) obtained with transcranial sonography (TCS) in animal and postmortem studies, our goal was to use this method in a disorder characterized with iron accumulation in human brain tissue. Therefore, magnetic resonance imaging (MRI) and TCS were conducted in 5 unrelated patients with pantothenate kinase-associated neurodegeneration (PKAN), caused by PANK2 mutations. All patients had an eye of the tiger sign. Hypointense lesions on the T2-weighted MRI images were restricted to the globus pallidus (GP) and SN. TCS also revealed bilateral hyperechogenicity restricted to the LN and SN, with normal DTV values. Both TCS and MRI studies in PKAN patients are in accordance with the pathological findings that accumulation of iron, even in advanced cases, is restricted to the GP and SN, suggesting selective involvement of these structures.