Clinico-genetic profile of seven patients with PARK-PINK1: A case series from a tertiary care centre from India and review of literature.

Background: Recessive variants in the PINK1 gene is a known cause of early-onset Parkinson's disease (EOPD).

Objective: To describe the clinical features and genetic profile of patients of PARK-PINK1.

Methods: Retrospective chart review of demographic, clinical and genetic details of patients carrying biallelic PINK1 variants from our database.

Result: Seven cases were recruited with median age at onset 33 years (Range: 20-49). All had asymmetrical onset, tremor in four, abnormal posturing in two and slowness in one patient. Parkinsonism phenotype was noted in six patients (with dystonia in four) and isolated dystonia in one. Among 6 patients with parkinsonism, five had rest tremor, all had good levodopa-response, and four had motor-fluctuation with choreiform-dyskinesia. Exome-sequencing revealed bi-allelic pathogenic/likely pathogenic variants in all of which five were novel.

Conclusion: PARK-PINK1 presents as an EOPD with tremor-predominant phenotype, good levodopa-responsiveness, early motor fluctuation and dyskinesia. We describe five novel variants in PINK1 gene.