Clinico-Genetic Profiles of Seven Patients With PINK1-Related Parkinson's Disease: A Case Series From a Tertiary Care Centre in India and a Review of the Literature.

Objective: Recessive variants in the PINK1 gene are known causes of early-onset Parkinson's disease (EOPD). To describe the clinical features and genetic profiles of patients with PINK1-related Parkinson's disease (PARK-PINK1) mutations.

Methods: We conducted a retrospective chart review of the demographic, clinical and genetic details of patients from our database carrying biallelic PINK1 variants.

Results: A total of 7 patients whose median age at onset was 33 years (range: 20-49) were recruited. All had asymmetrical onset, tremors were present in 4 patients, abnormal posturing was present in 2 patients, and slowness was present in 1 patient. The parkinsonism phenotype was noted in 6 patients (with dystonia in four) and isolated dystonia in one. Among the 6 patients with parkinsonism, five had rest tremors, all had good levodopa responses, and four had motor fluctuations with choreiform dyskinesia. Exome sequencing revealed biallelic pathogenic/likely pathogenic variants, five of which 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.