Electroencephalographic findings in asymptomatic relatives of patients with juvenile myoclonic epilepsy: relationship with the degree of kinship.

INTRODUCTION: A prevalence of 1 to 71% of electroencephalogram (EEG) abnormalities has been reported in asymptomatic relatives of patients with juvenile myoclonic epilepsy (JME). OBJECTIVE: To determine the frequency of EEG abnormalities in asymptomatic relatives of patients with JME according to the degree of kinship. METHODS: Prospective, analytical study. First-, second, and third-degree relatives of patients with JME who agreed to participate and signed informed consent were included. The analysis was descriptive, bivariate. RESULTS: 209 asymptomatic relatives were included, out of which 115 (55%) were females and 94 (45%) were males, with a mean age of 35.9 ± 16.9 (range between 6 and 73 years). Forty-four (21.1%) relatives had abnormal EEGs. First-degree relatives (12%) had abnormalities more frequently in comparison with second- and third-degree relatives (p = 0.007). CONCLUSIONS: EEG abnormalities were observed in one third of asymptomatic relatives. It is important to highlight that there were more alterations among first-degree relatives. In the future, these findings might enable for the risk of clinically developing the disease to be estimated and for genetic counseling to be provided.

INTRODUCCIÓN: Se ha reportado de 1 a 71 % de prevalencia de anormalidades en el electroencefalograma (EEG) de familiares asintomáticos de pacientes con epilepsia mioclónica juvenil (EMJ). OBJETIVO: Determinar la frecuencia de anormalidades en el EEG en familiares asintomáticos de pacientes con EMJ de acuerdo con el grado de parentesco. MÉTODOS: Estudio prospectivo y analítico. Se incluyeron familiares de primer, segundo y tercer grado de pacientes con EMJ, quienes aceptaron participar y firmaron el consentimiento informado. El análisis fue descriptivo bivariado. RESULTADOS: Se incluyeron 209 familiares asintomáticos, 115 (55 %) mujeres y 94 (45 %) hombres, con edad media de 35.9 ± 16.9 (rango entre seis y 73 años); 44 familiares (21.1 %) tuvieron EEG anormal. Los familiares de primer grado (12 %) cursaron con mayor frecuencia con anormalidades en comparación con los de segundo y tercer grado (p = 0.007). CONCLUSIONES: Se observaron anormalidades en el EEG de una tercera parte de los familiares asintomáticos. Es importante resaltar que existieron más alteraciones entre los familiares de primer grado. En un futuro, estos hallazgos permitirán estimar el riesgo de desarrollar la enfermedad clínicamente y brindar consejo genético.

Phenotyping juvenile myoclonic epilepsy. Praxis induction as a biomarker of unfavorable prognosis.

PURPOSE: Juvenile myoclonic epilepsy (JME) is a heterogeneous syndrome with seizures presenting typical fluctuation in diurnal cycle and relation with awakening. Few publications have approached clinical expressions of praxis induction (PI) in the nosology of JME as well as its impact on outcome. The aim of this study is to characterize PI as the only reflex trait in JME and its relation with prognosis. METHOD: JME with PI reported on a questionnaire and confirmed by video-EEG testing (Group 1, 20 patients) were compared with JME without any reflex epileptic trait (Group 2, 25 patients) and followed for a mean of 7.82 years (SD=3.98). Circadian distribution and frequency of seizures were assessed in a diary. Patients also had psychiatric evaluation. RESULTS: Prevalence of PI was 20/133 (15%) JME patients, and was predominant in males (1.5 male: 1 female; OR 13; p=0.042). Among Group 1 patients, only 2/20 presented seizures exclusively in the morning (p=0.013), and none, exclusively on awakening (p<0.001). PI patients had worse prognosis regarding control of myocloni (p=0.02) and absences (p=0.01); only 7/20 (35.0%) could be treated with VPA in monotherapy (p=0.01). At the last follow-up, 2/20 (10.0%) of Group 1 and 10 (40.0%) of Group 2 patients were free of all three seizure types (p=0.02). Even though relative risk of stress as a precipitant of seizures increased 3.82 times in Group 1, psychiatric comorbidities were not different between groups. CONCLUSION: PI reflex trait in JME is related to seizures without preferential circadian occurrence and reduced response to antiepileptic drugs.

Juvenile myoclonic epilepsy: psychiatric comorbidity and impact on outcome.

Juvenile myoclonic epilepsy (JME) is a well-defined age-related idiopathic epilepsy syndrome. Past studies have emphasized the difficulties in the treatment of patients with JME, which have been attributed to some specific psychiatric, psychological, and psychosocial characteristics. These aspects have aroused a significant amount of interest in the last two decades. In this article, the available studies that investigated the prevalence of psychiatric disorders (PDs) in JME and its impact on seizure outcome were reviewed in order to provide an update to clinicians about these two important aspects associated with this common epilepsy syndrome. The review disclosed a high prevalence of PDs in patients with JME, particularly mood, anxiety, and personality disorders. In addition, most recent studies have also observed that overall prevalence of PDs in JME has not shown statistically significant differences when compared with TLE, an epilepsy syndrome where the psychiatric aspects are most frequently studied. Taken together, data regarding the prevalence of PDs and their possible consequences on seizure outcome on JME indicate that special attention should be directed to psychological disturbances and psychiatric symptoms in this epilepsy syndrome. The early recognition and treatment of psychiatric symptoms, as well as psychological disturbances and psychosocial difficulties, should be considered fundamental to JME prognosis.

Psychiatric comorbidity in patients with two prototypes of focal versus generalized epilepsy syndromes.

The frequency of psychiatric disorders (PD) in a homogeneous series of patients with temporal lobe epilepsy with mesial temporal sclerosis (TLE-MTS) compared to patients with juvenile myoclonic epilepsy (JME) was evaluated, aiming to determine the frequency of PD and possible differences in psychiatric diagnoses between these two epileptic syndromes. Data from 248 patients with refractory TLE-MTS and from 124 JME patients were reviewed and compared. There was a high prevalence of PD in both groups of epilepsy patients, present in 100 TLE-MTS (41%) and in 58 JME patients (46.7%). Mood (23.7%), anxiety (13.7%) and psychotic (11.6%) disorders were the most frequent diagnoses in TLE-MTS group, while mood and anxiety disorders (25% and 21%, respectively) were the most common PD among JME. Psychoses were significantly associated with TLE-MTS (p=0.01). These observations are concordant with our previous study, reforcing the existence of a possible anatomic correlation of PD and brain structures involved in both epilepsy syndromes.

Novel mutations in Myoclonin1/EFHC1 in sporadic and familial juvenile myoclonic epilepsy.

BACKGROUND: Juvenile myoclonic epilepsy (JME) accounts for 3 to 12% of all epilepsies. In 2004, the GENESS Consortium demonstrated four missense mutations in Myoclonin1/EFHC1 of chromosome 6p12.1 segregating in 20% of Hispanic families with JME. OBJECTIVE: To examine what percentage of consecutive JME clinic cases have mutations in Myoclonin1/EFHC1. METHODS: We screened 44 consecutive patients from Mexico and Honduras and 67 patients from Japan using heteroduplex analysis and direct sequencing. RESULTS: We found five novel mutations in transcripts A and B of Myoclonin1/EFHC1. Two novel heterozygous missense mutations (c.755C>A and c.1523C>G) in transcript A occurred in both a singleton from Mexico and another singleton from Japan. A deletion/frameshift (C.789del.AV264fsx280) in transcript B was present in a mother and daughter from Mexico. A nonsense mutation (c.829C>T) in transcript B segregated in four clinically and seven epileptiform-EEG affected members of a large Honduran family. The same nonsense mutation (c.829C>T) occurred as a de novo mutation in a sporadic case. Finally, we found a three-base deletion (-364--362del.GAT) in the promoter region in a family from Japan. CONCLUSION: Nine percent of consecutive juvenile myoclonic epilepsy cases from Mexico and Honduras clinics and 3% of clinic patients from Japan carry mutations in Myoclonin1/EFCH1. These results represent the highest number and percentage of mutations found for a juvenile myoclonic epilepsy causing gene of any population group.

Psychiatric comorbidity in epilepsy: a study comparing patients with mesial temporal sclerosis and juvenile myoclonic epilepsy.

We evaluated the frequency of psychiatric disorders (PDs) in a homogenous series of patients with temporal lobe epilepsy with mesial temporal sclerosis (TLE-MTS), as compared with patients with juvenile myoclonic epilepsy (JME), aiming to determine possible differences in psychiatric diagnoses between these two epileptic syndromes. Data from 170 patients with refractory TLE-MTS and from 100 patients with JME were reviewed and compared. The prevalence of PDs was high in both groups of patients with epilepsy: PDs were present in 85 patients with TLE-MTS (50%) and 49 patients with JME (49%). Among the TLE-MTS group, mood (25.8%), psychotic (15.8%), and anxiety (14.1%) disorders were the most frequent diagnoses, whereas anxiety and mood disorders (23 and 19%, respectively) were the most common among patients with JME. Psychoses were significantly associated with MTS (P<0.01) and anxiety disorders with JME (P<0.05). These findings suggest the existence of an anatomic correlation between PDs and brain structures involved in both epilepsy syndromes.

Heterogeneity at the JME 6p11-12 locus: absence of mutations in the EFHC1 gene in linked Dutch families.

PURPOSE: The EFHC1 gene, encoding a protein with a Ca(2+)-sensing EF-hand motif, is localized at 6p12 and was recently reported as mutated in six Mexican juvenile myoclonic epilepsy (JME) families linked to this region. We had previously confirmed linkage between JME and 6p11-12 in 18 Dutch families, and shown exclusionary lod scores at 6p21.3. We therefore evaluated the relevance of EFHC1 in our set of 6p11-12-linked families. METHODS: We screened all coding and regulatory regions of EFHC1 by direct sequencing, and the detected variants were tested in a case-control association study. RESULTS: We found none of the five mutations previously reported in the Mexican families, but identified nine variants, three of which are novel: 5' upstream region (c.-146_147delGC), nonsynonymous (R159W, R182H, M448T, I619L), intronic (IVS3 + 10A>G, IVS8 + 175_176delTT, IVS10 + 59C>T), and 3' UTR (c.+121C>A). These variants did not cosegregate with JME and did not account for the observed linkage at the 6p11-12 locus. Furthermore, no significant association was detected between JME and these variants in 112 unrelated patients and 180 controls. Finally, none of the mutations reported in Mexican families was found in 100 unrelated patients. CONCLUSIONS: We found no evidence that EFHC1 is a major genetic risk factor for JME susceptibility in Dutch patients. The EFHC1 variants reported in Mexican families may be mendelian variants specific for those families, suggesting that for Dutch patients and possibly many other populations, the main disease variant at the 6p11-12 is yet to be identified.