Mitofusin 2 Variant Presenting With a Phenotype of Multiple System Atrophy of Cerebellar Subtype

• Published in: Neurology. Genetics 2024-02, Vol.10 (1), p.e200114
• Main Authors: Elbert, Adrienne, Dixon, Katherine, Shen, Yaoqing, Hamilton, Sara, Boerkoel, Cornelius F, Jones, Steven J, Kanungo, Anish K
• Format: Article
• Language: English
• Subjects: Clinical/Scientific Notes
• ISSN: 2376-7839; 2376-7839
• DOI: 10.1212/NXG.0000000000200114

To investigate the etiology of cerebellar ataxia in an adult male patient. We performed standard neurologic assessment and genome sequencing of a 62-year-old man with rapidly progressive balance and gait abnormalities. The propositus exhibited cognitive dysfunction, mild appendicular bradykinesia, prominent appendicular ataxia, dysarthria, and hypomimia with minimal dysautonomic symptoms. Nerve conduction studies showed mild peripheral sensory neuropathy and normal motor nerve conduction velocities. Brain imaging showed progressive cerebellar atrophy and gliosis of the olivopontocerebellar fibers, characterized by T2 hyperintensity within the pons. Genetic testing revealed a likely pathogenic germline variant in (NM_014874: c.[838C>T];[=], p.(R280C)) in the GTPase domain (G) interface; pathogenic variants of typically cause hereditary sensory and motor neuropathy VI or Charcot-Marie-Tooth disease 2A. The presence of progressive ataxia, "hot cross bun" sign, and dysautonomia has been associated with multiple system atrophy, cerebellar type (MSA-C). We describe progressive cerebellar ataxia in an individual with a deleterious variant in . Our findings suggest that pathogenic variants in can result in a spectrum of phenotypes including cerebellar ataxia with cerebellar-pontine atrophy in the absence of significant neuropathy and in a manner closely resembling MSA-C.