TWNK in Parkinson's Disease: A Movement Disorder and Mitochondrial Disease Center Perspective Study

Background: Parkinsonian features have been described in patients harboring variants in nuclear genes encoding for proteins involved in mitochondrial DNA maintenance, such as TWNK. Objectives: The aim was to screen for TWNK variants in an Italian cohort of Parkinson's disease (PD) patients and to assess the occurrence of parkinsonism in patients presenting with TWNK-related autosomal dominant progressive external ophthalmoplegia (TWNK-adPEO). Methods: Genomic DNA of 263 consecutively collected PD patients who underwent diagnostic genetic testing was analyzed with a targeted custom gene panel including TWNK, as well as genes causative of monogenic PD. Genetic and clinical data of 18 TWNK-adPEO patients with parkinsonism were retrospectively analyzed. Results: Six of 263 PD patients (2%), presenting either with isolated PD (n = 4) or in combination with bilateral ptosis (n = 2), carried TWNK likely pathogenic variants. Among 18 TWNK-adPEO patients, 5 (28%) had parkinsonism. Conclusions: We show candidate TWNK variants occurring in PD without PEO. This finding will require further confirmatory studies. © 2022 Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson Movement Disorder Society.