Novel KMT2B mutation causes cerebellar ataxia: Expanding the clinical phenotype.

Hereditary cerebellar ataxias comprise a heterogeneous group of neurodegenerative disorders affecting the cerebellum and/or cerebellar pathways. Next-generation sequencing techniques have contributed substantially to the expansion of ataxia-causing genes, including genes classically described in alternative phenotypes. Herein, we describe a patient with adult-onset cerebellar ataxia, minor dystonia, neuropathy, seizure and ophthalmological pathology, who bears a novel variant in KMT2B (NM_014727.2:c.3334 + 1G > A). Bioinformatic analysis suggested this variant completely abolished the splice-site at exon 8/intron 8, which was confirmed through analysis of mRNA extracted from fibroblasts. Exon 8 skipping would ultimately translate as an in-frame deletion at the protein level, corresponding to the loss of 91 aminoacids [p.(Gly1020_Asn1111del)]. So far, KMT2B disease causing variants have been described in patients with dystonia or neurodevelopmental delay, with no reports of a cerebellar predominant phenotype. Our findings highlight the possible role of KMT2B as a gene involved in hereditary cerebellar ataxias.

Social impairment and stigma in genetic generalized epilepsies.

INTRODUCTION: Patients with epilepsy have poor social outcome. Multifactorial factors are usually involved, but among them, stigma features may have an important role. Genetic generalized epilepsies (GGEs) were previously considered "benign" syndromes. The aim of our study was to assess social impairment and stigma in GGE and to evaluate differences between the following GGE subsyndromes: juvenile myoclonic epilepsy (JME), juvenile absence epilepsy (JAE), and generalized tonic-clonic seizures alone (GTCSA). Additionally, we compared these outcomes with outcomes from a cohort of patients with epilepsy with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS), a severe and difficult-to-treat syndrome. Results were compared with social data from the general population. METHODS: Adult patients with epilepsy with a previously classified GGE or MTLE-HS were consecutively invited to fill in a sociodemographic and stigma questionnaire in outpatient clinic. Clinical data and psychiatric comorbidities were retrieved from clinical notes. RESULTS: Questionnaires from 333 patients were obtained: 226/67% from patients with GGE (JME: 106/31.8%, GTCSA: 74/22.2%, and JAE: 46/13.8%) and 107/32.1% from patients with MTLE-HS. We found that patients with GGE have a good academic achievement but they have increased difficulties in finding a partner, higher rates of divorce, and a reduced number of children per woman and per man when compared with general population. We also observed that patients with GGE have higher rates of unemployment (22.6%) and lower monthly income than general population. Severe problems in housing were only seen in GGEs. Of these, 3 patients (1.3%) were in homeless condition. Over half (52%) of patients with MTLE-HS and over a quarter (28%) of patients with GGE experienced felt stigma. Psychiatric comorbidity was highly prevalent among GGE (34.1%), especially in patients with refractory epilepsy. Mood and anxiety disorders were the most prevalent conditions. No other significant differences were found between GGE subsyndromes. DISCUSSION: We found an impairment in every social domain assessed (except in level of education) when compared with general population. Most of the social outcome parameters were unexpectedly close or similar to MTLE-HS or even worse as it was the prevalence of homelessness among GGE. Social impairment is underdiagnosed and might be considered in clinical practice even in syndromes for some time considered benign such as GGE.

Apolipoprotein E isoforms and susceptibility to genetic generalized epilepsies.

Background: Apolipoprotein E (ApoE) is the main lipoprotein secreted in brain. It has a critical immunomodulatory function, influences neurotransmission and it is involved in repairing damaged neurons. ApoE e4 is an isoform of ApoE with altered function, and was previously associated with early onset epilepsy and refractoriness, both in animal models and in patients with focal epilepsies. There is a limited knowledge on ApoE's role in Genetic Generalized Epilepsies (GGE).Aim: To determine if ApoE isoforms are risk factors for GGE development.Methods: A group of 337 GGE patients (193 F, 144 M, 33.6 ± 14.2 years) was compared with a group of 342 healthy individuals in a case-control genetic association study. ApoE genotyping was performed using PCR-RFLP.Results: The genotypic frequency of ApoE e3/e2 was lower in GGE patients relative to controls (6.5% in GGE vs. 11.7% in controls, p = 0.019, OR (95% CI) = 0.53 (0.305-0.905). No associations with other clinical data such as photosensitivity or age at disease onset were observed.Conclusion: Our results show that ApoE e3/e2 genotype may be a protective factor for GGE development. There is evidence that this genotype could be neuroprotective, preventing oxidative damage and promoting neuronal survival. Although replication studies are warranted, our data suggest that ApoE isoforms have a role in epileptogenic mechanisms regardless of the specific epileptic manifestations.

Immunogenetic predisposing factors for mesial temporal lobe epilepsy with hippocampal sclerosis.

PURPOSE: Neuroinflammation appears as an important epileptogenic mechanism. Experimental and clinical studies have demonstrated an upregulation of pro-inflammatory cytokines such as IL-1ß and TNF-α, in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). Expression of these cytokines can be modulated by polymorphisms such as rs16944 and rs1800629, respectively, both of which have been associated with febrile seizures (FS) and MTLE-HS development. The human leukocyte antigen (HLA) system has also been implicated in diverse epileptic entities, suggesting a variable role of this system in epilepsy. Our aim was to analyse the association between immunogenetic factors and MTLE-HS development. For that rs16944 (-511 T>C, IL-1ß), rs1800629 (-308 G>A, TNF-α) polymorphisms and HLA-DRB1 locus were genotyped in a Portuguese Population. METHODS: We studied 196 MTLE-HS patients (108 females, 88 males, 44.7 ± 12.0 years, age of onset = 13.6 ± 10.3 years, 104 with FS antecedents) and 282 healthy controls in a case-control study. RESULTS: The frequency of rs16944 TT genotype was higher in MTLE-HS patients compared to controls (14.9% in MTLE-HS vs. 7.7% in controls, p = 0.021, OR [95% CI] = 2.20 [1.13-4.30]). This association was independent of FS antecedents. No association was observed between rs1800629 genotypes or HLA-DRB1 alleles and MTLE-HS susceptibility. Also, no correlation was observed between the studied polymorphisms and disease age of onset. CONCLUSION: The rs16944 TT genotype is associated with MTLE-HS development what may be explained by the higher IL-1ß levels produced by this genotype. High IL-1ß levels may have neurotoxic effects or imbalance neurotransmission leading to seizures.

Age of onset of mesial temporal lobe epilepsy with hippocampal sclerosis: the effect of apolipoprotein E and febrile seizures.

PURPOSE: Mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) is the most frequent pharmaco-resistant epilepsy. It has been associated with febrile seizures (FS) in childhood. Its aetiology remains unclear but genetic factors are involved. Apolipoprotein E (ApoE) is the main lipoprotein secreted in brain. It has a critical immunomodulatory function, influences neurotransmission and it is involved in repairing damaged neurons. ApoE ϵ4 is an isoform of ApoE with altered protein function, previously associated with refractoriness and early onset epilepsy. This study was undertaken to determine if ApoE isoforms are risk factors for MTLE-HS and influence clinical characteristics. METHODS: A group of 188 MTLE-HS patients (101 F, 87 M, mean age = 44.7 ± 11.6 years, 100 with FS antecedents) was studied and compared with a group of 342 healthy individuals in a case-control genetic association study. Data were analysed with Pearson Chi-squared Test or Student's t test, as appropriated. RESULTS: No differences in ApoE ϵ4 allelic frequencies between MTLE-HS patients and controls or between MTLE-HS subgroups were observed. Nevertheless, ApoE ϵ4 carriers had an earlier MTLE-HS onset (11.0 ± 7.9 years in ApoE ϵ4 carriers vs. 14.4 ± 11.2 years in ApoE ϵ4 non-carriers p < 0.05). Additionally, we observed that MTLE-HS patients with FS antecedents had a statistically significant early disease onset (11.5 ± 8.7 years in FS+ vs. 16.0 ± 12.1 years in FS-, p < 0.01). CONCLUSIONS: Our data show that ApoE ϵ4 and FS may not participate directly in etiopathogenic mechanisms of MTLE-HS but could hasten the disease development in predisposed individuals.

CNS involvement in V30M transthyretin amyloidosis: clinical, neuropathological and biochemical findings.

OBJECTIVES: Since liver transplant (LT) was introduced to treat patients with familial amyloid polyneuropathy carrying the V30M mutation (ATTR-V30M), ocular and cardiac complications have developed. Long-term central nervous system (CNS) involvement was not investigated. Our goals were to: (1) identify and characterise focal neurological episodes (FNEs) due to CNS dysfunction in ATTR-V30M patients; (2) characterise neuropathological features and temporal profile of CNS transthyretin amyloidosis. METHODS: We monitored the presence and type of FNEs in 87 consecutive ATTR-V30M and 35 non-ATTR LT patients. FNEs were investigated with CT scan, EEG and extensive neurovascular workup. MRI studies were not performed because all patients had cardiac pacemakers as part of the LT protocol. We characterised transthyretin amyloid deposition in the brains of seven ATTR-V30M patients, dead 3-13 years after polyneuropathy onset. RESULTS: FNEs occurred in 31% (27/87) of ATTR-V30M and in 5.7% (2/35) of the non-ATTR transplanted patients (OR=7.0, 95% CI 1.5 to 33.5). FNEs occurred on average 14.6 years after disease onset (95% CI 13.3 to 16.0) in ATTR-V30M patients, which is beyond the life expectancy of non-transplanted ATTR-V30M patients (10.9, 95% CI 10.5 to 11.3). ATTR-V30M patients with FNEs had longer disease duration (OR=1.24; 95% CI 1.07 to 1.43), renal dysfunction (OR=4.65; 95% CI 1.20 to 18.05) and were men (OR=3.57; 95% CI 1.02 to 12.30). CNS transthyretin amyloidosis was already present 3 years after polyneuropathy onset and progressed from the meninges and its vessels towards meningocortical vessels and the superficial brain parenchyma, as disease duration increased. CONCLUSIONS: Our findings indicate that CNS clinical involvement occurs in ATTR-V30M patients regardless of LT. Longer disease duration after LT can provide the necessary time for transthyretin amyloidosis to progress until it becomes clinically relevant. Highly sensitive imaging methods are needed to identify and monitor brain ATTR. Disease modifying therapies should consider brain TTR as a target.

Side-to-side axial movements. Adding a new sign to the asymmetry of the clonic phase and asymmetric seizure termination in differentiating primary and secondarily generalised tonic-clonic seizures.

AIM: To study new semiological signs which help distinguish between primary and secondarily generalised tonic-clonic seizures (GTCS). METHODS: We retrospectively studied 86 GTCS, 13 primary and 73 secondary, in 58 patients who underwent video-EEG (vEEG) evaluation in our epilepsy monitoring unit. Eleven patients had generalised epilepsy and 47 focal epilepsy. Two expert epileptologists, blinded to diagnosis, examined the vEEGs independently for the presence of five semiological signs. RESULTS: Asymmetry of limb movements in clonic phase, side-to-side axial movements, and asymmetric seizure termination occurred more frequently (p<0.05) in secondary GTCS compared to primary GTCS. Combining asymmetry of limb movements in clonic phase and side-to-side axial movements provided the greatest value in differentiating secondary GTCS from primary GTCS. CONCLUSION: Careful examination of GTCS seizure semiology can help differentiate primary from secondary GTCS. The semiological sign of side-to-side axial movements, which has not previously been studied in this context, may add to existing literature of semiological signs and be of value for the evaluation of surgical patients in the epilepsy monitoring unit. In the out-patient setting, a clear history of these signs may help guide drug treatment choices.

A rare case of tongue biting during sleep in childhood.

Bleeding tongue-biting episodes during sleep are a rare and alarming situation that can negatively impact the child's and parents' sleep, affecting their quality of life. Although highly suggestive of epilepsy, a differential diagnosis should be made with sleep-related movement disorders such as bruxism, hypnic myoclonus, facio-mandibular myoclonus, and geniospasm when this hypothesis is excluded. The clinical history, electroencephalogram, and video-polysomnography are essential for diagnostic assessment. Treatment with clonazepam can be necessary in the presence of frequent tongue biting that causes severe injuries and sleep disturbance. This study reports the challenging case of managing and diagnosing a 2-year-old boy with recurrent tongue biting during sleep since he was 12 months old, causing bleeding lacerations, frequent awakenings, and significant sleep impairment with daytime consequences for him and his family. CITATION: Cascais I, Ashworth J, Ribeiro L, Freitas J, Rios M. A rare case of tongue biting during sleep in childhood. J Clin Sleep Med. 2024;20(4):653-656.

Age-specific periictal electroclinical features of generalized tonic-clonic seizures and potential risk of sudden unexpected death in epilepsy (SUDEP).

Generalized tonic-clonic seizure (GTCS) is the commonest seizure type associated with sudden unexpected death in epilepsy (SUDEP). This study examined the semiological and electroencephalographic differences (EEG) in the GTCSs of adults as compared with those of children. The rationale lies on epidemiological observations that have noted a tenfold higher incidence of SUDEP in adults. We analyzed the video-EEG data of 105 GTCS events in 61 consecutive patients (12 children, 23 seizure events and 49 adults, 82 seizure events) recruited from the Epilepsy Monitoring Unit. Semiological, EEG, and 3-channel EKG features were studied. Periictal seizure phase durations were analyzed including tonic, clonic, total seizure, postictal EEG suppression (PGES), and recovery phases. Heart rate variability (HRV) measures including RMSSD (root mean square successive difference of RR intervals), SDNN (standard deviation of NN intervals), and SDSD (standard deviation of differences) were analyzed (including low frequency/high frequency power ratios) during preictal baseline and ictal and postictal phases. Generalized estimating equations (GEEs) were used to find associations between electroclinical features. Separate subgroup analyses were carried out on adult and pediatric age groups as well as medication groups (no antiepileptic medication cessation versus unchanged or reduced medication) during admission. Major differences were seen in adult and pediatric seizures with total seizure duration, tonic phase, PGES, and recovery phases being significantly shorter in children (p<0.01). Generalized estimating equation analysis, using tonic phase duration as the dependent variable, found age to correlate significantly (p<0.001), and this remained significant during subgroup analysis (adults and children) such that each 0.12-second increase in tonic phase duration correlated with a 1-second increase in PGES duration. Postictal EEG suppression durations were on average 28s shorter in children. With cessation of medication, total seizure duration was significantly increased by a mean value of 8s in children and 11s in adults (p<0.05). Tonic phase duration also significantly increased with medication cessation, and although PGES durations increased, this was not significant. Root mean square successive difference was negatively correlated with PGES duration (longer PGES durations were associated with decreased vagally mediated heart rate variability; p<0.05) but not with tonic phase duration. This study clearly points out identifiable electroclinical differences between adult and pediatric GTCSs that may be relevant in explaining lower SUDEP risk in children. The findings suggest that some prolonged seizure phases and prolonged PGES duration may be electroclinical markers of SUDEP risk and merit further study.

Different relationships between epilepsy syndromes and autoimmune diseases.

OBJECTIVE: Our objective was to study the relationship between epilepsy and autoimmune diseases in two different types of epilepsy: idiopathic generalized epilepsies (IGEs) and mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). The contribution of the human leukocyte antigen (HLA) system to this relationship was analyzed. METHODS: Adult patients with IGEs and MTLE-HS at a tertiary epilepsy center were consecutively enrolled between January 2016 and December 2020. RESULTS: A total of 664 patients, 422 with IGEs and 242 with MTLE-HS, were included. Patients with IGEs were 15 years younger, on average, than patients with MTLE-HS (p < .001). The frequency of autoimmune diseases was 5.5% (n = 23) and 4.5% (n = 11) in patients with IGEs and MTLE-HS, respectively (p = .716). The mean age of autoimmune disease onset was 20 ± 15.6 years in patients with IGEs and 36.7 ± 16.5 years in patients with MTLE-HS (p < .05). Clinical manifestations of autoimmune diseases preceded epilepsy onset in 30.4% of patients with IGEs (i.e., in early childhood); in the other patients, epilepsy appeared before autoimmune disease onset. In all but one patient with MTLE-HS and autoimmune diseases, the autoimmune diseases appeared after epilepsy onset from adolescence onward. SIGNIFICANCE: Our study indicates two relationship patterns: a bidirectional association between IGEs and autoimmune diseases and a unidirectional relationship between MTLE-HS and autoimmune diseases. The involvement of genetic susceptibility factors (such as the HLA system), autoinflammatory mechanisms, female sex, and antiseizure medications in these relationships are discussed.

Auditory verbal learning test can lateralize hippocampal sclerosis.

The ability of the Auditory Verbal Learning Test (AVLT) to lateralize hippocampal sclerosis (HS) in mesial temporal lobe epilepsy (MTLE) was explored in a sample of 50 patients with MTLE-HS (23 right and 27 left). Patients' AVLT scores were adjusted to the demographic characteristics of each individual in accordance with the Portuguese normative data. The laterality of the HS was determined by consensus by two neuroradiologists. ROC curves were used to identify the best AVLT cutoff scores to differentiate right vs. left HS. Diagnostic statistics were applied to different AVLT measures. The study results revealed that four AVLT scores can correctly classify the laterality of HS in the total sample and a sub-group of 39 right-handed patients (Edinburgh Laterality Inventory +100): delayed recall trial (76 and 80%, respectively), delayed recognition trial (64 and 67%, respectively), learning over trials index (64 and 74%, respectively), and long-term percent retention index (68 and 72%, respectively). In right-handed patients, the diagnostic capability of the delayed recall trial was improved by pairing it with the learning over trials index (accuracy of 85%). In sum, AVLT measures of verbal memory differentiate left from right HS in MTLE. The delayed recall trial demonstrated good diagnostic capacity.

Mesial Temporal Lobe Epilepsy (MTLE) Drug-Refractoriness Is Associated With P2X7 Receptors Overexpression in the Human Hippocampus and Temporal Neocortex and May Be Predicted by Low Circulating Levels of miR-22.

Objective: ATP-gated ionotropic P2X7 receptors (P2X7R) actively participate in epilepsy and other neurological disorders. Neocortical nerve terminals of patients with Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis (MTLE-HS) express higher P2X7R amounts. Overexpression of P2X7R bolsters ATP signals during seizures resulting in glial cell activation, cytokines production, and GABAergic rundown with unrestrained glutamatergic excitation. In a mouse model of status epilepticus, increased expression of P2X7R has been associated with the down-modulation of the non-coding micro RNA, miR-22. MiR levels are stable in biological fluids and normally reflect remote tissue production making them ideal disease biomarkers. Here, we compared P2X7R and miR-22 expression in epileptic brains and in the serum of patients with MTLE-HS, respectively. Methods: Quantitative RT-PCR was used to evaluate the expression of P2X7R in the hippocampus and anterior temporal lobe of 23 patients with MTLE-HS and 10 cadaveric controls. Confocal microscopy and Western blot analysis were performed to assess P2X7R protein amounts. MiR-22 expression was evaluated in cell-free sera of 40 MTLE-HS patients and 48 healthy controls. Results: Nerve terminals of the hippocampus and neocortical temporal lobe of MTLE-HS patients overexpress (p < 0.05) an 85 kDa P2X7R protein whereas the normally occurring 67 kDa receptor protein dominates in the brain of the cadaveric controls. Contrariwise, miR-22 serum levels are diminished (p < 0.001) in MTLE-HS patients compared to age-matched control blood donors, a situation that is more evident in patients requiring multiple (>3) anti-epileptic drug (AED) regimens. Conclusion: Data show that there is an inverse relationship between miR-22 serum levels and P2X7R expression in the hippocampus and neocortex of MTLE-HS patients, which implies that measuring serum miR-22 may be a clinical surrogate of P2X7R brain expression in the MTLE-HS. Moreover, the high area under the ROC curve (0.777; 95% CI 0.629-0.925; p = 0.001) suggests that low miR-22 serum levels may be a sensitive predictor of poor response to AEDs among MTLE-HS patients. Results also anticipate that targeting the miR-22/P2X7R axis may be a good strategy to develop newer AEDs.

Female preponderance in genetic generalized epilepsies.

INTRODUCTION: Epilepsy is more prevalent in men but Genetic Generalized Epilepsies (GGE) seem to be more common in women. A predominant maternal inheritance has been previously described in GGE. Our objective was to determine sex and inheritance patterns in a GGE population compared to mesial temporal lobe epilepsy with hippocampal sclerosis (MTLEHS). METHODS: We performed a prospective observational study including adult GGE and MTLEHS patients followed up at a tertiary epilepsy center from January 2016 to December 2019. Patients' familial history was obtained by a detailed questionnaire. Clinical and demographic data was retrieved from clinical notes. RESULTS: A cohort of 641 patients, 403 with GGE and 238 with MTLEHS, was analyzed. GGE was more common in women than MTLEHS (58.8% vs 44.5%, OR=1.63, p = 0.004). Compared to MTLEHS patients, more GGE patients had familial history of epilepsy (45.4% vs 25.2%; p<0.001). The GGE group had a higher percentage of female relatives with epilepsy (55% vs 37%; p = 0.006). The prevalence of maternal inheritance was not different between GGE and MTLEHS groups (62.9% vs 57.7%; p = 0.596). Photosensitivity was more common in females than in males (44.7% vs 34.3%, p = 0.036). CONCLUSION: There is a female preponderance in GGE when compared to MTLEHS, as both GGE patients and their affected relatives are more frequently women. The prevalence of maternal inheritance was not higher in GGE than in MTLEHS.

Immunogenetic protective factors in Genetic Generalized Epilepsy.

BACKGROUND: Genetic Generalized Epilepsies (GGEs) are a heterogeneous group of syndromes characterized by generalized seizure activity that affects both hemispheres, with mainly genetic causes. Neuroinflammation has been established as an important mechanism in epileptogenesis. The ability to develop an appropriated immune response is strongly determined by immunogenetic factors. In this setting, our aim was to evaluate potential associations between GGEs and immunogenetic factors. METHODS: The rs16944 (IL-1ß -511 T > C) polymorphism and the HLA-DRB1 locus were genotyped in a Portuguese GGE population. Association with two clinicopathological features, photosensitivity and refractoriness, was investigated. This case-control study included 323 GGE patients (187 F, 136 M, 34.0 ± 13.9 years of age), 145 of which with JME diagnosis (88 F, 57 M, 34.1 ± 14.0 years), and 282 healthy controls (174 F, 108 M, 37.7 ± 11.6 years). RESULTS: Decreased frequencies of the HLA-DRB1*09 and DRB1*13 alleles were observed in the GGE population. HLA-DRB1*07 frequency was increased in JME. Rs16944 allelic frequencies were similar between patients and controls. CONCLUSIONS: These results, not entirely consistent with previous reports, suggest that HLA molecules may have a complex role in epileptogenesis.

Two-year follow-up with eslicarbazepine acetate: a consecutive, retrospective, observational study.

PURPOSE: Eslicarbazepine acetate (ESL) is a new generation voltage-gated sodium channel blocker. It has completed one phase II clinical trial and three phase III clinical trials, two of which with 1-year open label extensions. ESL was approved in 2009 by the European Medicines Agency as adjunctive therapy in adults with partial-onset seizures with or without secondary generalization. It is marketed in Portugal since April 1st 2010. Despite good safety and efficacy shown in clinical trials, little is known about its effectiveness in a clinical day-to-day setting. Our purpose was to assess the post-marketing experience with ESL in our centre, in terms of safety and efficacy profile, and ascertain whether the results were comparable to the published data. METHODS: This is a retrospective, consecutive, single-centre 2-year observational study. All the patients who initiated treatment with ESL between April 1st 2010 and October 31st 2011 at Hospital de Santo António were consecutively included. Data was collected on demographics, clinical features, adverse events and treatment response, using a standardized data form. Follow-up data was considered until October 31st 2013. Efficacy analysis was performed using an "intention to treat" approach. KEY FINDINGS: We included 152 patients, 74 (48.7%) female. Mean age was 38.5 years-old (sd=14.2). Eight patients were less than 18 years old. Mean epilepsy duration was 26.8 (sd=13.1) years and mean seizure frequency in the previous 3 months was 19.7 seizures per month. At baseline, about 57.9% of all patients were taking ≤2 concomitant AEDs. The total adverse rate was 42.1% (64/152), with 50.0% (32/64) leading to treatment discontinuation. The most frequent adverse events were dizziness and somnolence/slowness. Adverse events were higher in regimens including carbamazepine, and mean age was higher in the patients reporting adverse events. Retention rates as estimated by Kaplan-Meyer curves were 82.9%, 71.3%, 65.1% and 62.8%, respectively, at 6, 12, 18 and 24 months. Retention time was not influenced by gender, diagnosis, age or epilepsy duration. Fifty-six patients (36.8%) dropped out of treatment, 32 (57.1%) due to adverse events, 19 (33.9%) due to lack of efficacy and 5 (8.9%) for other reasons. At 6,12,18 and 24 months, the responder rates were 25.7%, 25.7%, 19.0% and 17.1%, respectively and favourable global clinical impression rates were 27.7%, 19.7%, 17.8% and 16.5%. SIGNIFICANCE: This is the first study reporting follow-up data for up to 2 years in patients treated with ESL in the setting of daily clinical practice. The retention rates in our study are sustained throughout the 2 years of follow-up, and at 6 and 12 months are globally comparable to those of phase III trials and open-label extensions. The adverse event rate is also comparable to previous studies, and no new safety issues attributable to ESL were found. Responder rates were lower than those of previous studies, even though efficacy results must be interpreted with caution given the different study design. Thus, ESL appears to be a clinically useful add-on AED, with good safety profile and high retention rates, even in a very refractory group of patients like the presented cohort.

Unverricht-Lundborg disease: homozygosity for a new splicing mutation in the cystatin B gene.

Unverricht-Lundborg disease is the most common form of progressive myoclonic epilepsy (PME). It is due to cystatin B gene (CSTB) mutations. Several mutations in CSTB gene have been published, but few in homozygosity. We describe a patient with a new splicing alteration. Mutation Gln22Gln leads to abnormal splicing and partial inclusion of intronic sequence. This is one of the few cases of homozygosity for a non-classic mutation and adds to mutational heterogeneity of CSTB.