Objective: To report a very late-onset case of pantothenate kinase-associated neurodegeneration (PKAN) initially diagnosed as Parkinson’s disease.

Background: PKAN, the most common form of neurodegeneration with brain iron accumulation, usually begins in childhood. Onset after age 50 is exceptionally rare.

Method: Clinical evaluation, brain MRI, and genetic testing were performed in a 52-year-old man with progressive parkinsonism.

Results: The patient presented with a 2-year history of bradykinesia, rigidity, and postural instability, with minimal benefit from levodopa. Examination showed asymmetric parkinsonism, prominent oromandibular dystonia, spasticity, mild cognitive impairment, and continuous resting lingual tremor. Brain MRI demonstrated bilateral globus pallidus hypointensity with central T2 hyperintensity, consistent with the eye-of-the-tiger sign. Genetic testing identified two heterozygous PANK2 variants, including one previously reported pathogenic variant and one novel missense variant in the pantothenate kinase domain. The novel variant was ultra-rare in population databases, affected a highly conserved residue, and was predicted deleterious by multiple in silico tools.

Conclusion: PKAN should be considered in very late-onset parkinsonism with poor levodopa response, dystonia, and characteristic MRI findings. This case expands the clinical spectrum of adult-onset PKAN and highlights lingual tremor as a potentially underrecognized clue to PKAN in atypical parkinsonism.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/very-late-onset-pkan-presenting-with-parkinsonism-and-lingual-tremor-at-age-52/