Unverricht-Lundborg Disease Patients Research Articles

Generation of human induced pluripotent stem cell lines (UNIMGi003-A and UNIMGi004-A) from two Italian siblings affected by Unverricht-Lundborg disease

Unverricht-Lundborg disease (ULD) is an inherited form of progressive myoclonus epilepsy caused by mutations in the gene encoding Cystatin B (CSTB), an inhibitor of lysosomal proteases. The most common mutation described in ULD patients is an unstable expansion of a dodecamer sequence located in the CSTB gene promoter. This expansion is causative of the downregulation of CSTB gene expression and, consequently, of its inhibitory activity. Here we report the generation of induced pluripotent stem cell (iPSC) lines from two Italian siblings having a family history of ULD and affected by different clinical and pathological phenotypes of the disease.

Correction of a Splicing Mutation Affecting an Unverricht-Lundborg Disease Patient by Antisense Therapy.

Unverricht-Lundborg disease (ULD) is a common form of progressive myoclonic epilepsy caused by mutations in the cystatin B gene (CSTB) that encodes an inhibitor of several lysosomal cathepsins. Presently, only pharmacological treatment and psychosocial support are available for ULD patients. To overcome the pathogenic effect of the ULD splicing mutation c.66G>A (exon 1), we investigated whether an antisense oligonucleotide therapeutic strategy could correct the defect in patient cells. A specific locked nucleic acid (LNA) antisense oligonucleotide was designed to block a cryptic 5′ss in intron 1. Overall, this approach allowed the restoration of the normal splicing pattern. Furthermore, the recovery was both sequence and dose-specific. In general, this work provides a proof of principle on the correction of a CSTB gene defect causing ULD through a mutation-specific antisense therapy. It adds evidence to the feasibility of this approach, joining the many studies that are paving the way for translating antisense technology into the clinical practice. The insights detailed herein make mutation-based therapy a clear candidate for personalized treatment of ULD patients, encouraging similar investigations into other genetic diseases.

Perampanel in 12 patients with Unverricht-Lundborg disease.

Perampanel (PER) was used in 12 patients with Unverricht-Lundborg disease (ULD) to evaluate its efficacy against myoclonus and seizures. We treated 11 patients with EPM1 mutations (6 F, 5 M, aged 13-62 years) and a 43-year-old man with de novo KCNC1 mutation. PER was introduced by 2 mg steps at 2-4 week intervals until 6 mg/day, with a possible dose reduction or dose increase. Ten patients had a clear clinical response of myoclonus, and five were able to reduce concomitant therapy. Improvement was noted sometimes as soon as with 2 mg/day. Epileptic seizures stopped on PER in the six patients who still had experienced generalized tonic-clonic or myoclonic seizures (100%). Some abatement of efficacy on myoclonus was seen in two patients who still retained some benefit. Weight gain was reported in six patients (50%). Psychological and behavioral side-effects were observed in six patients (50%) and led to withdrawal of PER in three cases and dose reduction in three, with abatement of the problems. This study provides evidence that for ULD patients, PER may show marked efficacy even in severe cases, particularly against myoclonus, but also against seizures. PER should thus be tried in ULD patients whose seizures are not satisfactorily controlled. Its use is limited because of psychological and behavioral side effects, with higher doses of approximately 6 mg/day or greater likely risk factors.

Long-term follow-up of cortical hyperexcitability in Japanese Unverricht–Lundborg disease

PurposeTo delineate chronological changes of cortical hyperexcitability by long-term follow-up of the amplitudes of somatosensory evoked potentials (SEPs) in patients with Japanese Unverricht–Lundborg disease (ULD). MethodSEPs to median nerve stimulation were repeatedly examined in 7 genetically diagnosed ULD patients with the mean interval of 11.9 years. The degree of temporal changes in the amplitude of 3 early cortical components, N20, P25 and N35, to the age was analyzed and compared with that of healthy subjects. ResultsTheir clinical course was almost stable during the follow-up period, namely cessation of generalized tonic-clonic seizures and little or no progression of myoclonus. SEP amplitudes of P25 and N35 were enlarged in all patients and were gradually decreased with aging in ULD on average. The degree of temporal changes of P25 and N35 in ULD was similar or even lower than that of healthy subjects. ConclusionEnlarged but relatively stable SEP amplitudes had a consistency with so-called self-limited clinical course in Japanese ULD. SEP amplitude could be one of the surrogate markers of the degree of cortical hyperexcitability in ULD during the long-term follow-up period.

Seizure control in Unverricht-Lundborg disease: a single-centre study.

New antiepileptic drug (AED) options for generalised seizure types have been adopted for use as treatment for Unverricht-Lundborg disease. Whether this has led to improved seizure control or functional outcome in ULD patients remains obscure. We retrospectively identified all patients seen at Helsinki University Hospital due to Unverricht-Lundborg disease during 2003-2008 in order to determine which AED treatments had been retained for long-term use. The majority of the patients had severe functional disabilities. In the year preceding the last hospital visit, all patients (n=20) were receiving polytherapy and 14 patients had been free of tonic-clonic seizures. During follow-up, improvement in myoclonia had been recorded for the majority of patients with either add-on piracetam, topiramate, or levetiracetam, but valproate was still in use by all patients. Treatment with lamotrigine had been started and retained less often relative to other AEDs. Add-on AED treatment was often associated with significant adverse effects. Unverricht-Lundborg disease patients may benefit from add-on treatment with levetiracetam or topiramate for seizure control. Treatment of eventual comorbidities with other than AEDs is also discussed.

A Shared Haplotype Indicates a Founder Event in Unverricht–Lundborg Disease Patients from Serbia

Unverricht–Lundborg disease (ULD) is an autosomal recessive disorder caused by dodecamer repeat expansion in the promoter region of the cystatin B (CSTB) gene in approximately 90% of the disease alleles worldwide. This study presents results of genetic findings in four Serbian unrelated patients with clinical and molecular diagnosis of ULD. Using newly established PCR protocol with betaine, we detected a homozygous expansion of dodecamer repeats in the CSTB gene in four patients with clinical diagnosis of ULD. Our results are in agreement with previous studies showing that dodecamer repeats expansion is the most common mutation associated with ULD. Haplotype analysis of eight unrelated ULD chromosomes was performed using seven markers flanking CSTB gene and one intragenic variant. We demonstrated the existence of a founder effect, strongly supported by LD calculations. Size of the minimal common haplotype implies that the most recent common ancestor of the Serbian ULD patients lived about 110 generations ago. We showed that Serbian ULD patients share the same common ancestor with patients from Baltic countries and North Africa. In the light of our data, we proposed extended minimal common haplotype, which could be considered as initial haplotype of the founder event common for Serbian, Baltic, and North African ULD patients.

Decreased cortical excitability in Unverricht–Lundborg disease in the long-term follow-up: A consecutive SEP study

Objective To delineate long-term change of cortical excitability by measuring somatosensory evoked potentials (SEPs) in patients with Unverricht–Lundborg disease (ULD). Methods SEPs to median nerve stimulation were repeatedly examined in two genetically proven ULD patients manifesting stable condition over 16 years, namely disabling but non-progressive myoclonus and cessation of generalised tonic–clonic seizures. Results In both patients, five sets of early cortical components were identified 16 years ago: two tangential components of N20–P20 and P30–N30 and three radial components of P25, N35 and N40. Cortical SEPs were regarded as abnormally enhanced ‘giant’ based on the N35 amplitude (>mean + 3 SD of normal controls). The bimodal negative peaks of N35 and N40 showed different spatial distribution: N35 maximum in the central area and N40 in the centro-parietal area. At present, N35 remained giant while N40 disappeared in both patients. Conclusions It is possible that currently preserved giant SEPs at least at N35 reflect disabling cortical myoclonus and that disappearance of N40 might reflect a lesser degree of increased cortico-cortical connectivity and/or decreased cortical hyperexcitability in the association cortices. It might possibly have resulted in the disappearance of GTCSs. Significance We delineated long-term change of giant SEP in ULD.

Abnormal ERD/ERS but Unaffected BOLD Response in Patients with Unverricht–Lundborg Disease During Index Extension: A Simultaneous EEG-fMRI Study

Electrophysiological studies indicate that Unverricht-Lundborg's disease (ULD), the most common form of progressive myoclonus epilepsy in Europe, is characterized by the involvement of multiple cortical regions in degenerative changes that lead to enhanced excitation and deficient inhibition. We searched for the haemodynamic correlates of these effects using functional MRI (fMRI) of self-paced index extensions, a well-accepted task highlighting significant differences. EEG and fMRI were simultaneously acquired in 11 ULD patients and 16 controls, performing the index extensions individually (event-related task) as well as repetitively (block task). ERD/ERS analysis was performed for the EEG data in the alpha and beta bands. fMRI time-series were analyzed using the traditional general linear model, as well as with an assumption-free approach, and by means of cross-region correlations representing functional connectivity. In line with the existing literature, ULD patients had enhanced desynchronization in the alpha band and reduced post-movement synchronization in the beta band. By contrast, fMRI did not reveal any difference between the two groups; there were no activation intensity, latency or extent effects, no significant engagement of additional regions, and no changes to functional connectivity. We conclude that, so long as the patients are executing a task which does not induce obvious action myoclonus, the hypothesized abnormalities in pyramidal neuron and interneuron dynamics are relatively subtle, embodied in processes which are not metabolically-demanding and take place at a time-scale invisible to fMRI.

T2-weighted high-intensity signals in the basal ganglia as an interesting image finding in Unverricht-Lundborg disease

We conducted a search for white matter changes (WMCs) in 13 Unverricht-Lundborg disease patients and compared the prevalence of WMCs in these patients to age-matched long-term epileptics and healthy controls. ULD patients had significantly more T2-weighted high-intensity signals on MRI than control subjects, due to the increased prevalence of these signals in the basal ganglia. Interestingly, ULD patients with the basal ganglia changes were overweight. Basal ganglia T2-weighted high-intensity signals are novel findings in ULD.

Death in Unverricht–Lundborg disease

The objective of this study is to report cases of unexpected deaths in Unverricht-Lundborg disease (ULD) patients, a comparatively benign form of progressive myoclonus epilepsy. We performed a multicentric study of the circumstances of death in ULD patients seen in the last 16 years. We assessed age, sex, severity and duration of disease, antiepileptic drugs, circumstances and presumed cause of death. Nineteen observations (12 females, 7 males) were collected from four centers (Tunis, Marseille, Milan, Belgrade). The most common causes of death are (1) SUDEP (six cases, all female), with 4/6 on phenobarbital alone, and (2) complications of severe ULD (six cases). Two patients committed suicide. Only one death was clearly unrelated to ULD (car accident), while four patients died of stroke, drowning, complications of chronic alcoholism and Wernicke encephalopathy, respectively. In conclusion, although the prognosis of ULD has progressed, there are still spontaneously severe forms and high risk of early death, including SUDEP.

The neuropsychological pattern of Unverricht–Lundborg disease

This study determined the neuropsychological pattern of Unverricht-Lundborg disease (ULD) and its relationship to disease-related variables. Twenty-one ULD patients were evaluated using neuropsychological tests for abstract reasoning, attention, planning, set-shifting, theory of mind, visual perception, visuomotor coordination, ideomotor, orofacial and constructive praxis, language, learning, and memory. The control groups consisted of 21 healthy subjects and 21 patients with cryptogenic temporal lobe epilepsy (TLE). Multivariate analysis of variance showed that, in comparison with both control groups, the ULD patients showed significantly impaired abstract reasoning, attention, planning, word fluency, constructive praxis, and visuospatial memory and learning. Factor analysis of the test scores obtained by the ULD and TLE groups identified four factors (processing and execution, praxis, memory, theory of mind), and separate ANOVAs using epilepsy-related and demographic variables as covariates showed that the ULD patients had significantly impaired processing and execution. Correlation and regression analyses showed that processing and execution was significantly associated with diagnosis, disease duration and education, and logistic regression analyses indicated that it significantly predicted a diagnosis of ULD. To conclude, ULD is characterised by impaired processing and execution functions. This impairment is a strong independent predictor of ULD and may contribute to the characterisation of the diagnosis.

Substantial Thalamostriatal Dopaminergic Defect in Unverricht‐Lundborg Disease

Unverricht-Lundborg disease (ULD) is currently classified as progressive myoclonus epilepsy. Myoclonus, the characteristic symptom in ULD, suggests that dopamine neurotransmission may be involved in the pathophysiology of ULD. Our purpose was to examine brain dopaminergic function in ULD patients. Four genetically and clinically diagnosed ULD patients and eight healthy controls were scanned with [(11)C]raclopride-PET. PET images were coregistered to individual 1.5 T MR images and region-of-interest analysis was performed for the striatum and thalamus. Standardized uptake values and individual voxel-wise binding potential maps of the patients and controls were also analyzed. ULD patients had markedly higher (31-54%) dopamine D2-like receptor availabilities than healthy controls in both the striatum and the thalamus. The proportionally highest binding potentials were detected in the thalamus. There were no significant differences in the cerebellar uptake of [(11)C]raclopride in ULD patients versus healthy controls. Voxel-based results were in accordance with the region-of-interest analysis. These results suggest that dopaminergic modulation at the level of the striatum and thalamus could be a crucial factor contributing to the symptoms of ULD. In the light of our data, we propose that ULD with dopamine dysfunction and dyskinetic symptoms shares certain pathophysiological mechanisms with classical movement disorders. Future studies are therefore warranted to study the effect of dopaminergic pharmacotherapy in ULD.

Movement-related desynchronization-synchronization (ERD/ERS) in patients with Unverricht–Lundborg disease

We studied changes in event-related desynchronization/synchronization (ERD/ERS) patterns in patients with Unverricht–Lundborg disease (ULD), presenting with prominent action myoclonus. We analyzed the movement-related ERD/ERS in α and β frequency bands in 15 patients using self-paced finger extension as a motor paradigm and we compared the results with those obtained in 12 healthy volunteers. In all ULD patients, α- and β-ERD regularly occurred with onset and location similar to that found in healthy controls, but the desynchronization of α activity was significantly greater than in controls (C3: − 64.4 ± 9.8% vs. − 49.7 ± 14.8%; p = 0.004). Moreover, in the patients, both α- and β-ERD spread toward frontal electrodes. In controls, the post-movement β-ERS regularly occurred; it was absent in eight patients with severe action myoclonus, while, in seven patients with mild or moderate myoclonus, the β-peak was significantly smaller with respect to that measured in controls (55.6 ± 15.1% vs. 153.9 ± 99.8%, p = 0.006). The failure of β-ERS well-correlated with motor impairment resulting from action myoclonus, whereas SSEPs and long-loop reflexes performed to detect signs of cortical hyperexcitability showed inconsistent changes. In ULD patients, ERD/ERS changes indicate an increased activation of motor cortex during movement planning and a great reduction of post-excitatory inhibition of motor cortex. The changes involving β-ERS had a significant relationship with the functional disability in individual patients and might play a pathogenic role in the motor dysfunction.

Sensorimotor cortex excitability in Unverricht–Lundborg disease and Lafora body disease

To investigate whether Unverricht-Lundborg disease (ULD) and Lafora body disease (LBD) can be differentiated on the basis of their neurophysiologic profiles. Somatosensory evoked potentials (SSEPs), long-loop reflexes (LLRs), and the influence of conditioning nerve stimulation on the motor potentials evoked by transcranial stimulation in 8 patients with LBD and 10 patients with ULD were investigated. Both groups showed sensorimotor cortex hyperexcitability, but their electrophysiologic profiles were different. Enlarged P25 to N33 SSEP components and enhanced LLRs were common in the ULD patients, whereas medium-latency "giant" SSEP components and less consistently enhanced LLRs were more frequently found in the patients with LBD. Cortical relay time was extremely brief in ULD but varied in LBD. Conditioning somatosensory stimuli differently affected motor cortex excitability, leading to early facilitation in ULD and delayed and prolonged facilitation in LBD. Patients with Unverricht-Lundborg disease (ULD) and Lafora body disease (LBD) have different electrophysiologic profiles. The ULD findings point to an aberrant subcortical or cortical loop (possibly short-cutting the somatosensory cortex) that is involved in generating the prominent action myoclonus characterizing the disorder. The LBD findings highlight sustained hyperexcitability of the sensorimotor cortex in response to afferent stimuli, which fit with a more severe impairment of inhibitory mechanisms.

Founder Effect in Patients with Unverricht‐Lundborg Disease on Reunion Island

Unverricht-Lundborg disease (ULD) is the most frequent form of progressive myoclonus epilepsy. ULD is caused mostly by a homozygous expansion of a dodecamer repeat in the cystatin B gene (CSTB) promoter. We present here a clinical and molecular study of 14 ULD patients originating from Reunion Island, a French island in the Indian Ocean. These ULD patients were clinically evaluated, and the diagnosis of ULD was confirmed molecularly. We analyzed 12 microsatellites flanking CSTB and estimated the date of introduction of the ULD mutation on Reunion Island. These cases were clinically very similar, with the typical myoclonus syndrome associated with generalized tonic-clonic seizures, cerebellar involvement and, in some cases, mild mental deterioration. The mean age at onset was 9.6 years (range, 5-14 years), and the mean disease duration was 27 years (range, 5-47 years). The 14 patients harbored the typical ULD mutation, with variable degrees of expansion (mean of 56.3 repeats; range, 49-63). A founder effect was detected, with all but one of the Reunion ULD chromosomes displaying expansions belonging to the same haplotype, 1-1-1-2-6-4-3. We estimated the date of arrival of the most recent common ancestor (MRCA) of these patients on Reunion Island to the middle of the eighteenth century. These Reunion ULD patients displayed a homogeneous phenotype. Our molecular results are compatible with the instability of the repeat expansion and revealed a founder effect in Reunion ULD patients and the existence of a MRCA about 12 generations ago.

Haplotype study of West European and North African Unverricht-Lundborg chromosomes: evidence for a few founder mutations.

Unverricht-Lundborg disease (ULD) is a progressive myoclonus epilepsy common in Finland and North Africa, and less common in Western Europe. ULD is mostly caused by expansion of a dodecamer repeat in the cystatin B gene ( CSTB) promoter. We performed a haplotype study of ULD chromosomes (ULDc) with the repeat expansion. We included 48 West European Caucasian (WEC) and 47 North African (NA) ULDc. We analysed eight markers flanking CSTB(GT10-D21S1890-D21S1885-D21S2040-D21S1259- CSTB-D21S1912-PFKL-D21S171) and one intragenic variant in the CSTB 3' UTR (A2575G). We observed a founder effect in most of the NA ULD patients, as 61.7% of the NA ULDc (29/47) shared the same haplotype, A1 (1-1-A-1-6-7), for markers D21S1885-D21S2040-A2575G-D21S1259-D21S1912-PFKL. Moreover, if we considered only the markers D21S1885, D21S2040, A2575G and D21S1259, 43 of the 47 NA ULDc shared the same alleles 1-1-A-1, haplotype A. As previously shown, the WEC ULDc were heterogeneous. However, the Baltic haplotype, A3 (5-1-1-A-1-1), was observed in ten WEC ULDc (20.8%) and the CSTB 3'UTR variant, which we called the Alps variant, was observed in 17 ULDc (35.4%). Finally, as almost all NA patients, like Scandinavian patients, were of the haplotype A, we assumed that there was an ancient common founder effect in NA and Baltic ULD patients. We estimated that the putative most recent common ancestral ULD carrier with this haplotype A must have existed about 2,500 years ago (100-150 generations). Finally, this work provides evidence for the existence of only a small number of founder mutations in ULD.

Cortical sensorimotor alterations in Unverricht-Lundborg disease patients without generalized seizures

We investigated cortical functions of two Unverricht-Lundborg disease (ULD) patients suffering from myoclonic jerks, but no generalized tonic-clonic seizures. Somatosensory cortical responses were recorded to median nerve stimuli and coherence was calculated between cortical and muscle signals during isometric contraction of hand muscle. In contrast to ULD patients with generalized tonic-clonic seizures, responses of the primary somatosensory (SI) cortex were only slightly enhanced in the left and normal in the right hemisphere, and no early responses were observed in the ipsilateral SI. Cortex-muscle coherence was remarkably enhanced. We conclude that in ULD patients without generalized tonic-clonic seizures, both the excitability of the SI and transcallosal conduction are relatively normal, probably decreasing susceptibility to generalized seizures. Disturbed cortical control of muscle contraction indicates selective alteration of the motor cortex activation.