Background: While researchers pursue the etiology, pathophysiology and treatment of movement disorders, presently there is no biological marker for the two most common disorders – essential tremor (ET), and Parkinson’s disease and variants (Parkinson syndrome, or PS). The diagnosis of each remains clinical, but definitive diagnosis is made on brain pathology. Population epidemiological studies are hampered by a lack of diagnostic precision. Twins with the same disorder are scarce, and the next best option is studies of well-documented first-degree family members. Methods: Patients were seen at the Saskatchewan Movement Disorders Program (SMDP). All autopsied cases with known clinicopathological diagnosis of a movement disorder between 1970 and 2019 were reviewed. Only those with a first-degree family member – parent, child, and/or sibling - with a movement disorder were included. Results: 671 cases with movement disorders seen at SMDP have been autopsied. 29 cases including probands were found and thirteen first-degree families were identified; eight families were multiple (2 or more) siblings and five families included one parent/one child. In seven families, the diagnosis was concordant. Conclusions: Movement disorders in first degree relatives with autopsied verified diagnosis are dissimilar in nearly half the cases. Such small intensively studied groups offer unique research opportunities.