No evidence of a role for cystatin B gene in juvenile myoclonic epilepsy

Diagnostic and therapeutic approach to drug-resistant juvenile myoclonic epilepsy

INTRODUCTION

Juvenile myoclonic epilepsy (JME), also known as Janz syndrome, is a common form of generalized epilepsy of presumed genetic origin representing up to 10% of all epilepsy cases. Despite adequate anti-seizure medication (ASM) treatment, seizures persist in one-third of JME patients.

AREAS COVERED

A literature search was conducted using Pubmed search on the topics of drug-resistant JME.

EXPERT OPINION

About 30% of JME patients are drug-resistant. Valproate (VPA) is considered the first-choice drug. In women of childbearing potential, levetiracetam (LEV) should represent the first-choice treatment. Alternative monotherapy or add-on therapy should be considered in subjects with resistant seizures after the exclusion of pseudo-drug resistance. The choice of the add-on ASM depends on the predominant seizure type. In subjects with persistent bilateral tonic-clonic seizures, LEV or lamotrigine should be firstly considered. In patients with difficult-to-treat myoclonic seizures, clonazepam or LEV are recommended. In case of persistent absences, ethosuximide should be considered. With appropriate selection and safeguards in place, VPA should remain available as an option in women of childbearing potential whose seizures are resistant to other treatments.

Drug-Resistant Juvenile Myoclonic Epilepsy: Misdiagnosis of Progressive Myoclonus Epilepsy

Juvenile myoclonic epilepsy (JME) is a common epilepsy syndrome characterized by bilateral myoclonic and tonic-clonic seizures typically starting in adolescence and responding well to medication. Misdiagnosis of a more severe progressive myoclonus epilepsy (PME) as JME has been suggested as a cause of drug-resistance. Medical records of the Epilepsy Center Hessen-Marburg between 2005 and 2014 were automatically selected using keywords and manually reviewed regarding the presence of a JME diagnosis at any timepoint. The identified patients were evaluated regarding seizure outcome and drug resistance according to ILAE criteria. 87/168 identified JME patients were seizure-free at last follow-up including 61 drug-responsive patients (group NDR). Seventy-eight patients were not seizure-free including 26 drug-resistant patients (group DR). Valproate was the most efficacious AED. The JME diagnosis was revised in 7 patients of group DR including 6 in whom the diagnosis had already been questioned or revised during clinical follow-up. One of these was finally diagnosed with PME (genetically confirmed Lafora disease) based on genetic testing. She was initially reviewed at age 29 yrs and considered to be inconsistent with PME. Intellectual disability (p = 0.025), cognitive impairment (p < 0.001), febrile seizures in first-degree relatives (p = 0.023) and prominent dialeptic seizures (p = 0.009) where significantly more frequent in group DR. Individuals with PME are rarely found among drug-resistant alleged JME patients in a tertiary epilepsy center. Even a very detailed review by experienced epileptologists may not identify the presence of PME before the typical features evolve underpinning the need for early genetic testing in drug-resistant JME patients.

CSTB Downregulation Promotes Cell Proliferation and Migration and Suppresses Apoptosis in Gastric Cancer SGC-7901 Cell Line

This study aimed to investigate the pivotal role of cystatin B (CSTB) in the development of gastric cancer and to explore its possible regulatory mechanism. Human gastric cancer SGC-7901 cells as a model in vitro were transfected with plasmid PCDNA3.1-CSTB and siRNA-CSTB using Lipofectamine 2000. Quantitative real-time PCR (qRT-PCR) and Western blotting were performed to determine the relative expression of CSTB and PI3K/Akt/mTOR pathway-related protein. Moreover, MTT assay, Transwell assay, and flow cytometry were used to assess cell proliferation, migration, and apoptosis, respectively. The results showed that CSTB was significantly downregulated in SGC-7901 cells compared with gastric epithelial cells. CSTB was successfully overexpressed and suppressed after cells were transfected with pc-CSTB and si-CSTB, respectively. Moreover, cell viability and migration were significantly decreased after being transfected with pc-CSTB when compared with the control group, while being obviously increased after transfection with si-CSTB. However, cell apoptosis was significantly induced after being transfected with pc-CSTB, while being obviously suppressed after transfection with si-CSTB. Besides, the expression levels of p-PI3K, p-Akt, and p-mTOR proteins were all significantly decreased in the pc-CSTB transfection group when compared with the control group, while being increased in the si-CSTB transfection group. Our findings suggest that CSTB downregulation may promote the development of gastric cancer by affecting cell proliferation and migration, and the PI3K/Akt/mTOR signaling pathway was activated in this process. CSTB may serve as a potential therapeutic target for gastric cancer.

A novel c132-134del mutation in Unverricht-Lundborg disease and the review of literature of heterozygous compound patients

Unverricht-Lundborg disease or progressive myoclonic epilepsy type 1 (EPM1) is an autosomal recessive disease caused by mutation of the cystatin B gene (CSTB), located on chromosome 21q22.3. The most common mutation is an expansion of unstable dodecamer repetition (CCCCGCCCCGCG), whereas other types of mutations are rare. Among these, heterozygous compound mutations are described to induce a more severe phenotype than that of homozygous dodecameric repetition. We report two siblings affected by heterozygous compound mutations carrying a novel mutation of the deletion of three nucleotides in exon 2 of the gene in position 132-134 of the coding sequence (c.132-134del) in the allele not including the dodecamer repetition. This mutation results in the loss of two amino acid residues and insertion of an asparagine in position 44 (p.Lys44_Ser45delinsAsn). Our patients presented a very different clinical picture. The male patient had a severe myoclonus, drug-resistant epilepsy and psychiatric comorbidity, while his affected sister had only very rare seizures and sporadic myoclonic jerks at awakening. The revision of literature about heterozygous compound EPM1 patients confirms this gender phenotypic expressivity, with female patients carrying less severe symptoms than male patients. These data lead to the hypothesis of complex gender-specific factors interacting with CSTB expressivity in EPM1 patients.