Atypical Parkinsonian (AT) syndromes are a group of progressive neurodegenerative disorders that are one of the leading causes of fatality and dementia in the elderly. Progressive supranuclear palsy (PSP), Multiple system atrophy (MSA), Corticobasal degeneration (CBD), and other overlap syndromes are the significant types. Globally there are few large studies of these disorders and few from India. In this prospective longitudinal study, we envisage prospectively recruiting a large cohort of patients with AT and thoroughly characterizing them by detailed clinical phenotyping by clinical assessment, genetic evaluation, neuroimaging using advanced MRI techniques, biological sampling for biomarker testing sleep studies (PSG), Optical coherence tomography (OCT), and cellbased studies (IPSCs). These patients will then be followed up by actively following up and periodic assessments for the previously recorded parameters at baseline and at least one or two times over the next 3 years up to a maximum till the study duration. This data will be used to identify patterns and changes and help us prepare disease-specific models for phenotype, genetics, biomarker, and neuroimaging. This unique native dataset on atypical parkinsonian disorders will provide a better understanding of risks and demography and advance information on biomarkers.