PANK1 and neurodegeneration with brain iron accumulation: These disorders are classified based on genetic differences. The most common NBIA disorder is autosomal recessive pantothenate kinase-associated neurodegeneration (PKAN). PKAN is commonly associated with the eye-of-the-tiger sign; for instance, in one study, 100% of the examined PKAN cases had an eye-of-the-tiger sign on brain MRI [2].