EARLY-ONSET STROKE ASSOCIATED WITH A MUTATION IN MITOFUSIN 2

Abstract

Mitofusin 2 ( MFN2 ) gene encodes an outer mitochondrial membrane protein which plays a central role in mitochondrial fusion.1 Mutations in the MFN2 gene have recently been reported to cause up to 33% of axonal peripheral neuropathies which in some cases involved the CNS.2,3 Since an initial study, which linked MFN2 mutations with Charcot-Marie-Tooth disease type 2A (CMT2A),4 MFN2 mutations have also been found in CMT with optic atrophy (CMT6).5 MFN2 prevents cell death following DNA damage and K+ deprivation induced apoptosis beyond its role of mitochondrial fusion.6 Furthermore, it has been reported that mitochondrial fusion defect is an early event of ischemic stroke.7 We report a case with early-onset stroke putatively caused by a novel MFN2 mutation. To our knowledge, no previous report has been published concerning CNS involvement without peripheral neuropathy caused by MFN2 mutations. ### Case reports. #### Patient 1. The proband was admitted at 12 years of age because of sudden development of vomiting and gait ataxia. She did not show any delay in developmental milestones. In tandem gait, she kept veering to the right side, and showed marked intention tremor. Laboratory examinations disclosed elevated plasma lactate (42.6 mg/dL; normal: 7.4–27.1 mg/dL) and pyruvate levels (0.78 mg/dL; normal: 0.30–0.70 mg/dL). The ratio of lactate/pyruvate was 54.6 (normal: 10–20). In addition, her hemoglobin …