Neuropathologic Findings in a Patient with Juvenile-Onset Levodopa-Responsive Parkinsonism Due to ATP13A2 Mutation

Objective To describe the postmortem neuropathologic findings of a patient with Kufor Rakeb syndrome (KRS) due to ATP13A2 mutation. KRS is characterized by juvenile-onset levodopa-responsive parkinsonism associated with pyramidal signs, supranuclear gaze palsy, and cognitive impairment. Methods A detailed neuropathologic analysis of the brain was performed. The patient had a genetically confirmed ATP13A2 homozygous missense mutation and died at age 38 years, which was 26 years after the onset of his symptoms. Results The main brain neuropathologic findings were widespread neuronal and glial lipofuscin accumulation with no Lewy body-type inclusions and absence of α-synuclein-positive, tau-positive, β-amyloid-positive, and TDP-43 protein-positive pathologies. Sparse iron deposits were observed in several brain areas, but no obvious axonal spheroids were identified. Discussion This is to our knowledge the first KRS postmortem neuropathologic description. Iron deposits were found but not associated with increased axonal spheroids, as frequently observed in neurodegeneration with brain iron accumulation. ATP13A2 mutations have been described in patients with neuronal ceroid lipofuscinosis (CLN). Moreover, animal models with these mutations develop neurodegenerative disorders with CLN pathology. Therefore, our findings support that ATP13A2 mutations may be considered a genetic etiology of neuronal lipofuscinosis.