‘Atypical’ Parkinson's disease – genetic

Genetic atypical Parkinson's disease (PD) describes monogenic forms of PD that resemble idiopathic PD but feature prominent atypical clinical signs and symptoms and can be sub-grouped into i) atypical monogenic forms caused by mutations in the ATP13A2, DNAJC6, FBXO7, SYNJ1, VPS13C, and DCTN genes; ii) monogenic PD more closely resembling idiopathic PD, but associated with atypical features in at least a subset of cases (SNCA-, LRRK2-, VPS35-, Parkin-, PINK1-, and DJ-1-linked PD; iii) carriers of mutations in genes that are usually associated with other movement disorders but may present with parkinsonism, such as dopa-responsive dystonia. Some atypical features are shared by almost all forms, such as an overall early age at onset. Other clinical signs are present in carriers of mutations across several different genes, such as for example, early cognitive decline. Finally, several clinical features can serve as red flags for specific forms of atypical PD including a supranuclear gaze palsy in ATP13A2 mutation carriers or hypoventilation linked to mutations in the DCTN1 gene.