A novel SEMA6B variant causes adult-onset progressive myoclonic epilepsy-11 in a Chinese family: A case report and literature review

This study describes a patient with progressive myoclonic epilepsy-11 (EPM-11), which follows autosomal dominant inheritance caused by a novel SEMA6B variant. Most patients develop this disease during infancy or adolescence with action myoclonus, generalized tonic-clonic seizures (GTCS), and progressive neurological deterioration. No cases of adult-onset EPM-11 have been reported yet. Here, we present one case of adult-onset EPM-11 who experienced gait instability, seizures, and cognitive impairment, and harbored a novel missense variant, c.432C>G (p.C144W). Our findings provide a foundation for a better understanding of the phenotypic and genotypic profiles of EPM-11. Further functional studies are recommended to elucidate the pathogenesis of this disease.

[1]  Yan Chen,et al.  Non-convulsive Status Epilepticus in SEMA6B-Related Progressive Myoclonic Epilepsy: A Case Report With Literature Review , 2022, Frontiers in Pediatrics.

[2]  Ya-qin Wang,et al.  A Frameshift Variant in the SEMA6B Gene Causes Global Developmental Delay and Febrile Seizures , 2021, Neuroscience Bulletin.

[3]  N. Brüggemann,et al.  Zonisamide‐responsive myoclonus in SEMA6B‐associated progressive myoclonic epilepsy , 2021, Annals of clinical and translational neurology.

[4]  Yuan Fang,et al.  Novel Truncating and Missense Variants in SEMA6B in Patients With Early-Onset Epilepsy , 2021, Frontiers in Cell and Developmental Biology.

[5]  I. Scheffer,et al.  Progressive myoclonus epilepsies-Residual unsolved cases have marked genetic heterogeneity including dolichol-dependent protein glycosylation pathway genes. , 2021, American journal of human genetics.

[6]  Qian Li,et al.  A De Novo SEMA6B Variant in a Chinese Patient with Progressive Myoclonic Epilepsy-11 and Review of the Literature , 2021, Journal of Molecular Neuroscience.

[7]  A. R. Mohamed,et al.  De Novo Truncating Variants in the Last Exon of SEMA6B Cause Progressive Myoclonic Epilepsy. , 2020, American journal of human genetics.

[8]  I. Krantz,et al.  Redefining the Etiologic Landscape of Cerebellar Malformations. , 2019, American journal of human genetics.

[9]  P. Striano,et al.  The history of progressive myoclonus epilepsies. , 2016, Epileptic disorders : international epilepsy journal with videotape.

[10]  R. Kälviäinen.  Progressive Myoclonus Epilepsies , 2015 .

[11]  Nicole H. Wilson,et al.  Semaphorin 6B acts as a receptor in post-crossing commissural axon guidance , 2014, Development.

[12]  P. Striano,et al.  Progressive myoclonic epilepsies , 2014, Neurology.

[13]  B. Minassian.  The progressive myoclonus epilepsies. , 2014, Progress in brain research.

[14]  J. Conry,et al.  Zonisamide for the treatment of myoclonic seizures in progressive myoclonic epilepsy: an open-label study. , 2008, Epileptic disorders : international epilepsy journal with videotape.

[15]  N. Delanty,et al.  Progressive myoclonic epilepsies: a review of genetic and therapeutic aspects , 2005, The Lancet Neurology.

[16]  A. Simpson,et al.  Human semaphorin 6B [(HSA)SEMA6B], a novel human class 6 semaphorin gene: alternative splicing and all-trans-retinoic acid-dependent downregulation in glioblastoma cell lines. , 2001, Genomics.

[17]  Andermann.  Classification of progressive myoclonus epilepsies and related disorders , 1990, Annals of neurology.

[18]  F. Andermann,et al.  Progressive myoclonus epilepsies: specific causes and diagnosis. , 1986, The New England journal of medicine.