Uniting around the uncommon: MDS Study Group collaborates to advance our understanding of rare disorders

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The Rare Movement Disorders (RMD) Study Group was established in 2016 to foster international collaboration and improve understanding of rare movement disorders. Although individually uncommon, these conditions collectively represent millions of people worldwide, and present significant clinical and research challenges owing to their heterogeneity, diagnostic complexity, and limited evidence base. The Study Group seeks to advance progress in this field by facilitating collaboration, encouraging research, and promoting education within the International Parkinson and Movement Disorder Society (MDS) community.

Since its formation, the study group has grown to include more than 320 members from around the world. It provides a platform for clinicians and researchers to exchange expertise, develop collaborative projects, and discuss challenging cases within a supportive international network.

One of the study group’s most valued educational initiatives is the Rare Movement Disorders Case Conference, a quarterly virtual forum. These sessions provide an interactive setting in which clinicians can present complex or illustrative cases. Discussions typically focus on diagnostic reasoning, genetic findings, imaging features, and treatment considerations. The meetings have become a valuable forum for education, mentorship, and the exchange of ideas across institutions and continents. Several upcoming cases are already scheduled, and the group hopes these conferences will continue to grow as a vibrant platform for learning and collaboration. We encourage MDS members with an interest in rare movement disorders to join our captivating case conferences, either to present a case or to improve their knowledge about rare diseases, diagnostic skills, and complex case management.

A number of collaborative research initiatives have already resulted in publications that highlight both scientific findings and broader challenges in the field. For example, a highly-cited global survey conducted by the study group examined access to genetic testing for movement disorders across 109 countries.¹ The results revealed substantial international disparities, with many regions reporting limited access to genetic testing, geneticists, and genetic counselling services. Financial barriers and differences in healthcare infrastructure were identified as important factors influencing access, underscoring the need for continued advocacy and collaboration to improve diagnostic resources worldwide.

An accurate genetic diagnosis may also have important implications for treatment decisions. Recent work from the group has highlighted the relevance of genetic background for outcomes of deep brain stimulation (DBS) in dystonia.² Furthermore, challenging the common perception that genetic disorders cannot be treated, a comprehensive review emphasized the important therapeutic implications that may arise from identifying specific inherited movement disorders.³

Progress in the diagnosis and management of these conditions continues to stimulate new collaborative research initiatives within the study group, including international case series on VAC14-related dystonia-parkinsonism and polycythaemia vera-associated movement disorders, movement disorders associated with haemochromatosis, and diabetic striatopathy, as well as exploring further efficacy data for DBS in a diverse group of genetic dystonia. Colleagues who have encountered such cases and are interested in contributing are warmly invited to contact us.

Looking ahead, the Rare Movement Disorders Study Group aims to further expand its collaborative network and research activities while continuing to strengthen its educational initiatives. Through these efforts, the group hopes to contribute to improving knowledge, diagnosis, and care for patients living with rare movement disorders worldwide.

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References

1. Gatto EM, Walker RH, Gonzalez C, Cesarini M, Cossu G, Stephen CD, Balint B, Rodríguez-Violante M, Jankovic J, Morgante F, Jinnah HA; Rare Movement Disorders Study Group of the International Parkinson Disease, Movement Disorders Society. Worldwide barriers to genetic testing for movement disorders. Eur J Neurol. 2021 Jun;28(6):1901-1909. doi: 10.1111/ene.14826. Epub 2021 Apr 9. PMID: 33730413.
2. Sarva H, Rodriguez-Porcel F, Rivera F, Gonzalez CD, Barkan S, Tripathi S, Gatto E, Ruiz PG; Rare Movement Disorders Study Group of the International Parkinsons and Movement Disorders Society. The role of genetics in the treatment of dystonia with deep brain stimulation: Systematic review and Meta-analysis. J Neurol Sci. 2024 Apr 15;459:122970. doi: 10.1016/j.jns.2024.122970. Epub 2024 Mar 20. PMID: 38520940.
3. Jinnah HA, Albanese A, Bhatia KP, Cardoso F, Da Prat G, de Koning TJ, Espay AJ, Fung V, Garcia-Ruiz PJ, Gershanik O, Jankovic J, Kaji R, Kotschet K, Marras C, Miyasaki JM, Morgante F, Munchau A, Pal PK, Rodriguez Oroz MC, Rodríguez-Violante M, Schöls L, Stamelou M, Tijssen M, Uribe Roca C, de la Cerda A, Gatto EM; International Parkinson's Disease Movement Disorders Society Task Force on Rare Movement Disorders. Treatable inherited rare movement disorders. Mov Disord. 2018 Jan;33(1):21-35. doi: 10.1002/mds.27140. Epub 2017 Sep 1. PMID: 28861905; PMCID: PMC5921079.