P149 – 2652: Neuroimaging findings in two common NBIA subtypes, PKAN and MPAN

Objective The two most common subtypes of NBIA (neurodegeneration with brain iron accumulation; formerly called as Hallervorden-Spatz syndrome) in Poland are PKAN and MPAN, caused by mutations in PANK2 and C19orf12, respectively. Characteristic findings in brain MRI are valuable to distinguish between different forms of NBIA and perform efficient genetic testing. Methods We evaluated brain MRIs from 41 patients with PKAN and in 30 patients with MPAN. We determined the degree of change in signal intensity in different brain regions with a focus on the basal ganglia and substantia nigra. We performed genetic testing to confirm the presence of mutations in PKAN2 and C19orf12. Results All 41 patients with PKAN showed a specific T2-weighted hyperintensity within a hypointense area in the globus pallidus, described as an eye-of-the-tiger sign. 30 patients with MPAN revealed a hypointense signal in the globus pallidus and in the substantia nigra. Brain MRI in younger patients with PKAN initially revealed only hyperintense signal with surrounding small hypointense signal in globus pallidus. Younger subjects with MPAN revealed only presence of hypointense signal in globus pallidus and in substantia nigra, which size increased with age of the patients. Evaluations performed in patients with PKAN and MPAN demonstrated no other abnormalities in other brain structures. Conclusion Patients with PKAN and MPAN are distinguishable based on characteristic brain MRI patterns, which makes it possible to refer them for molecular evaluation in order to confirm a preliminary diagnosis.