Two novel variants of VPS13C gene related Parkinsonism: A case report and literature review.

RATIONALE: Mutations in the vacuolar protein sorting 13 homolog C (VPS13C) gene have been associated with Parkinson disease (PD). However, the mutation of VPS13C in Parkinsonism is uncommon and the clinical characteristics are highly heterogeneous. This study identifies 2 novel pathogenic variants in VPS13C, with particular emphasis on follow-up brain magnetic resonance imaging (MRI) images. PATIENT CONCERNS: The patient first exhibited resting tremor in the right limb at the age of 26. As the disease progressed, he developed bradykinesia, rigidity, gait instability, cognitive decline, dysarthria, myoclonus, depressed mood, irritability, and aggression. He was treated with levodopa/benserazide, pramipexole, and rasagiline, but the benefit was only temporary. By the age of 32, his gait instability was further aggravated, manifested as frequent falls, requiring bed rest or wheelchair use. Follow-up brain MRI showed progressive cortical atrophy. Whole-exome sequencing of the patient revealed compound heterozygous pathogenic variants (c.1699C > T, chr15: 62156504-62352664) in VPS13C. DIAGNOSES: VPS13C-related early onset PD. INTERVENTIONS: The patient was treated with levodopa/benserazide 125 mg 4 times daily, rasagiline 1 mg once daily, donepezil 5 mg once nightly, and quetiapine 50 mg once nightly. OUTCOMES: After 6 months of follow-up, his symptoms were further aggravated. LESSONS: This study identifies 2 novel pathogenic variants in VPS13C, expanding the known mutational spectrum of the gene. Additionally, brain MRI may serve as a potential imaging marker for disease progression. A review of the literature indicates that VPS13C-related Parkinsonism appears as a heterogeneous disorder, including PD and dementia with Lewy bodies. VPS13C mutations are highly diverse, with point mutations being the most common, followed by splice-site variants. Genetic screening is essential for an accurate diagnosis and distinction between different forms of early onset PD. This increases clinicians' understanding of the clinical and genetic characteristics of VPS13C-related Parkinsonism.