Identification of a Novel Homozygous Splice-Site Mutation in that Causes Progressive Myoclonus Epilepsy with or without Renal Failure / 中华医学杂志(英文版)

<p><b>Background</b>Progressive myoclonus epilepsies (PMEs) comprise a group of rare genetic disorders characterized by action myoclonus, epileptic seizures, and ataxia with progressive neurologic decline. Due to clinical and genetic heterogeneity of PMEs, it is difficult to decide which genes are affected. The aim of this study was to report an action myoclonus with or without renal failure syndrome (EPM4) family and summarize the clinical and genetic characteristics of all reported EPM4 patients.</p><p><b>Methods</b>In the present study, targeted next-generation sequencing (NGS) was applied to screen causative genes in a Chinese PME family. The candidate variant was further confirmed by cosegregation analysis and further functional analysis, including the reverse transcription polymerase chain reaction and Western blot of the proband's muscle. Moreover, literature data on the clinical and mutational features of all reported EPM4 patients were reviewed.</p><p><b>Results</b>The gene analysis revealed a novel homozygous splicing mutation (c.995-1G>A) of the SCARB2 gene in two brothers. Further functional analysis revealed that this mutation led to loss function of the SCARB2 protein. The classification of the candidate variant, according to the American College of Medical Genetics and Genomics standards and guidelines and functional analysis, was pathogenic. Therefore, these two brothers were finally diagnostically confirmed as EPM4.</p><p><b>Conclusions</b>These present results suggest the potential for targeted NGS to conduct a more rapid and precise diagnosis for PME patients. A literature review revealed that mutations in the different functional domains of SCARB2 appear to be associated with the phenotype of EPM4.</p>

CLN6 Mutation in a Patient with Progressive Myoclonus Epilepsy / 대한소아신경학회지

Neuronal ceroid lipofuscinoses (NCLs) are inherited neurodegenerative disorders, which are caused by the accumulation of lipopigment in lysosomes. Variant forms of late infantile NCLs (vLINCLs) characterized by a later onset of seizures and visual impairment (3–8 years) than in the classic form (2–4 years) are caused by mutations of the gene encoding ceroid lipofuscinosis neuronal protein 6 (CLN6). In a girl with progressive myoclonus epilepsy, we found heterozygous variants of CLN6 (NM_017882.2; NP_060352.1): c.296A>G (p.Lys99Arg) and c.307C>T (p.Arg103Trp). They were identified with whole-exome sequencing and verified with Sanger sequencing. At 7 years and 9 months, our patient had developed multiple types of seizures, prominent myoclonus with photosensitivity, regression in motor and language skills, pyramidal and extrapyramidal signs, and brain atrophy in brain images, all of which were progressive and were compatible with vLINCLs. However, this first Korean report shows no visual impairment, which resembles the previously reported Japanese case.

Clinical Manifestations and Pathology of Progressive Myoclonus Epilepsy / 中国康复理论与实践

@#Objective To explore the various types of progressive myoclonus epilepsy seizure characteristics, diagnostic strategies, and pathological features.Methods12 cases of progressive myoclonus epilepsy were analyzed with the clinical characteristics, the routine laboratory examinations, the pathological examination by light and electron microscopy to extra cranial.Results12 cases carried out routine examinations, neural electrophysiological examinations and physical examinations. The result showed that there 5 patients diagnosed with Neuronal Ceroid Lipofuscinoses, 5 patients with MERRF, 1 patient with Lafora Disease, 1 patient with Unverricht-Lundborg disease.ConclusionProgressive myoclonus epilepsy is a group of rare myoclonus epilepsy syndrome. It can be early diagnosed and properly classified with detailed medical history, characteristics of the EEG, and physical examination of extra cranial tissue, especially electron microscopy examination.

A Case of Dentatorubropallidoluysian Atrophy with Progressive Myoclonus Epilepsy

The dentatorubropallidoluysian atrophy (DRPLA) is a neurodegenerative disorder with expansion of an unstable CAG trinucleotide repeat in a gene on chromosome 12 and a rare cause of progressive myoclonus epilepsy (PME). A 34-year-old female showed progressive myoclonus, choreoathetosis, generalized tonicclonic seizure, dementia and ataxia. Her uncle died during convulsion at the age of 19. Brain MRI revealed cerebral, cerebellar and brainstem atrophy accompanied by dilatation of the fourth ventricle. The demonstration of expanded CAG repeat (67/11) in the gene for DRPLA was used to confirm the diagnosis. (J Korean Neurol Assoc 19(2):173~175, 2001)

A Case of Dentatorubropallidoluysian Atrophy with Progressive Myoclonus Epilepsy

The dentatorubropallidoluysian atrophy (DRPLA) is a neurodegenerative disorder with expansion of an unstable CAG trinucleotide repeat in a gene on chromosome 12 and a rare cause of progressive myoclonus epilepsy (PME). A 34-year-old female showed progressive myoclonus, choreoathetosis, generalized tonicclonic seizure, dementia and ataxia. Her uncle died during convulsion at the age of 19. Brain MRI revealed cerebral, cerebellar and brainstem atrophy accompanied by dilatation of the fourth ventricle. The demonstration of expanded CAG repeat (67/11) in the gene for DRPLA was used to confirm the diagnosis. (J Korean Neurol Assoc 19(2):173~175, 2001)

Two Cases of Progressive Myoclonus Epilepsy due to Gaucher's Disease, Type 3

Gaucher's disease is an autosomal recessive disorder caused by a deficiency of beta-glucosidase (glucocerebrosidase) which results in an accumulation of glucocerebroside in various organs and tissues. Type 3 (juvenile or subacute neuro-pathic) Gaucher's disease, presented here as progressive myoclonus epilepsy, occurs more rarely than type 1 (adult or nonneuropathic) or type 2 (infantile or neuropathic) Gaucher's disease. Two patients (brother and sister) with type 3 Gaucher's disease had or was expected to develop typical features of progressive myoclonus epilepsy: myoclonus, seizures, dementia, and cerebellar dysfunction. One of them showed Gaucher cells in a liver biopsy specimen and decreased beta-glucosidase activity (14% of normal) in the cultured skin fibroblasts, which confirmed the clinical diagno-sis of type 3 Gaucher's disease.