Clinical characteristics of 80 subjects with KCNQ2-related encephalopathy: Results from a family-driven survey.

Variants of KCNQ2 are associated with a wide spectrum of disorders, ranging from Self-limiting Neonatal Epilepsy (SelNE) to Early Onset Developmental and Epileptic Encephalopathy (KCNQ2-DEE). Comorbidities associated with this end of the spectrum have been seldomly described and their impact on the life of patients and their families is yet to be investigated. Collaborating with caregivers from different European family associations, we have developed a questionnaire aimed at investigating the onset and frequency of epileptic seizures, anti-seizure medications (ASM), hospitalizations, stages of development, and comorbidities. Responses from 80 patients, 40 males, from 14 countries have been collected. Median age 7.6 years (4 months - 43.6 years). Of 76 epileptic patients (93.6%), 55.3% were seizure-free with a mean age at last seizure of 26.7 months. Among patients with active epilepsy, those older have a lower frequency of seizures (p > 0.05). We were able to identify three different clusters of varying severity (Mild, Severe, Profound), based on neurodevelopmental features and symptoms, excluding epilepsy. Patients in a higher severity cluster had a higher mean number of comorbidities, which had a higher impact on families. Notably, patients in different clusters presented different epilepsy onset and courses. This study constitutes the most extensive data collection of patients with KCNQ2-DEE, with a focus on comorbidities in a wide age group. The participation of caregivers helps to define the impact of the disease on the lives of patients and families and can help identify new primary and secondary outcomes beyond seizures in future studies.

Electroclinical findings and long-term outcomes in epileptic patients with inv dup (15).

OBJECTIVE: To define the electroclinical phenotype and long-term outcomes in a cohort of patients with inv dup (15) syndrome. MATERIAL AND METHODS: The electroclinical data of 45 patients (25 males) affected by inv dup (15) and seizures were retrospectively analysed, and long-term follow-up of epilepsy was evaluated. RESULTS: Epilepsy onset was marked by generalized seizures in 53% of patients, epileptic spasms in 51%, focal seizures in 26%, atypical absences in 11% and epileptic falls in 9%. The epileptic syndromes defined were: generalized epilepsy (26.7%), focal epilepsy (22.3%), epileptic encephalopathy with epileptic spasms as the only seizure type (17.7%) and Lennox-Gastaut syndrome (33.3%). Drug-resistant epilepsy was detected in 55.5% of patients. There was a significant higher prevalence of seizure-free patients in those with seizure onset after the age of 5 years and with focal epilepsy, with respect to those with earlier epilepsy onset because most of these later developed an epileptic encephalopathy (69.2% vs 34.4%; P = .03), usually Lennox-Gastaut Syndrome in type. In fact, among patients with early-onset epilepsy, those presenting with epileptic spasms as the only seizure type associated with classical hypsarrhythmia achieved seizure freedom (P < .001) compared to patients with spasms and other seizure types associated with modified hypsarrhythmia. CONCLUSIONS: Epilepsy in inv dup (15) leads to a more severe burden of disease. Frequently, these patients show drug resistance, in particular when epilepsy onset is before the age of five and features epileptic encephalopathy.

Early-onset absence epilepsy: SLC2A1 gene analysis and treatment evolution.

BACKGROUND AND PURPOSES: To determine the prevalence of SLC2A1 mutations in children with early-onset absence epilepsy (EOAE) and to investigate whether there were differences in demographic and electroclinical data between patients who became seizure-free with anti-epileptic drug (AED) monotherapy (group I) and those who needed add-on treatment of a second AED (group II). METHODS: We reviewed children with EOAE attending different Italian epilepsy centers. All participants had onset of absence seizures within the first 3 years of life but otherwise conformed to a strict definition of childhood absence epilepsy. Mutation analysis of SLC2A1 was performed in each patient. RESULTS: Eighty-four children (57 in group I, 27 in group II) fulfilled the inclusion criteria. No mutation in SLC2A1 was found. There were no statistical differences between the two groups with regard to F/M ratio, age at onset of EOAE, early history of febrile seizures, first-degree family history for genetic generalized epilepsy, duration of AED therapy at 3 years after enrollment, use of AEDs at 3 years, failed withdrawals at 3 years, terminal remission of EOAE at 3 years, and 6-month follow-up EEG data. Mean duration of seizures/active epilepsy was significantly shorter in group I than in group II (P = 0.008). CONCLUSIONS: We demonstrate that in a large series of children with rigorous diagnosis of EOAE, no mutations in SLC2A1 gene are detected. Except for duration of seizures/active epilepsy, no significant differences in demographic and electroclinical aspects are observed between children with EOAE who responded well to AED monotherapy and those who became seizure-free with add-on treatment of a second AED.

Refining the phenotype associated with MEF2C haploinsufficiency.

Recently, submicroscopic deletions of the 5q14.3 region have been described in patients with severe mental retardation (MR), stereotypic movements, epilepsy and cerebral malformations. Further delineation of a critical region of overlap in these patients pointed to MEF2C as the responsible gene. This finding was further reinforced by the identification of a nonsense mutation in a patient with a similar phenotype. In brain, MEF2C is essential for early neurogenesis, neuronal migration and differentiation. Here we present two additional patients with severe MR, autism spectrum disorder and epilepsy, carrying a very small deletion encompassing the MEF2C gene. This finding strengthens the role of this gene in severe MR, and enables further delineation of the clinical phenotype.

Periventricular heterotopia: phenotypic heterogeneity and correlation with Filamin A mutations.

Periventricular heterotopia (PH) occurs when collections of neurons lay along the lateral ventricles or just beneath. Human Filamin A gene (FLNA) mutations are associated with classical X-linked bilateral periventricular nodular heterotopia (PNH), featuring contiguous heterotopic nodules, mega cisterna magna, cardiovascular malformations and epilepsy. FLNA encodes an F-actin-binding cytoplasmic phosphoprotein and is involved in early brain neurogenesis and neuronal migration. A rare, recessive form of bilateral PNH with microcephaly and severe delay is associated with mutations of the ADP-ribosylation factor guanine nucleotide-exchange factor-2 (ARFGEF2) gene, required for vesicle and membrane trafficking from the trans-Golgi. However, PH is a heterogeneous disorder. We studied clinical and brain MRI of 182 patients with PH and, based on its anatomic distribution and associated birth defects, identified 15 subtypes. Classical bilateral PNH represented the largest group (98 patients: 54%). The 14 additional phenotypes (84 patients: 46%) included PNH with Ehlers-Danlos syndrome (EDS), temporo-occipital PNH with hippocampal malformation and cerebellar hypoplasia, PNH with fronto-perisylvian or temporo-occipital polymicrogyria, posterior PNH with hydrocephalus, PNH with microcephaly, PNH with frontonasal dysplasia, PNH with limb abnormalities, PNH with fragile-X syndrome, PNH with ambiguous genitalia, micronodular PH, unilateral PNH, laminar ribbon-like and linear PH. We performed mutation analysis of FLNA in 120 patients, of whom 72 (60%) had classical bilateral PNH and 48 (40%) other PH phenotypes, and identified 25 mutations in 40 individuals. Sixteen mutations had not been reported previously. Mutations were found in 35 patients with classical bilateral PNH, in three with PNH with EDS and in two with unilateral PNH. Twenty one mutations were nonsense and frame-shift and four missense. The high prevalence of mutations causing protein truncations confirms that loss of function is the major cause of the disorder. FLNA mutations were found in 100% of familial cases with X-linked PNH (10 families: 8 with classical bilateral PNH, 1 with EDS and 1 with unilateral PH) and in 26% of sporadic patients with classical bilateral PNH. Overall, mutations occurred in 49% of individuals with classical bilateral PNH irrespective of their being familial or sporadic. However, the chances of finding a mutation were exceedingly gender biased with 93% of mutations occurring in females and 7% in males. The probability of finding FLNA mutations in other phenotypes was 4% but was limited to the minor variants of PNH with EDS and unilateral PNH. Statistical analysis considering all 42 mutations described so far identifies a hotspot region for PNH in the actin-binding domain (P < 0.05).

Molecular and genomic characterisation of cryptic chromosomal alterations leading to paternal duplication of the 11p15.5 Beckwith-Wiedemann region.

BACKGROUND: Beckwith-Wiedemann syndrome (BWS) is an overgrowth disorder with increased risk of paediatric tumours. The aetiology involves epigenetic and genetic alterations affecting the 11p15 region, methylation of the differentially methylated DMR2 region being the most common defect, while less frequent aetiologies include mosaic paternal 11p uniparental disomy (11patUPD), maternally inherited mutations of the CDKN1C gene, and hypermethylation of DMR1. A few patients have cytogenetic abnormalities involving 11p15.5. METHODS: Screening of 70 trios of BWS probands for 11p mosaic paternal UPD and for cryptic cytogenetic rearrangements using microsatellite segregation analysis identified a profile compatible with paternal 11p15 duplication in two patients. RESULTS: Fluorescence in situ hybridisation analysis revealed in one case the unbalanced translocation der(21)t(11;21)(p15.4;q22.3) originated from missegregation of a cryptic paternal balanced translocation. The second patient, trisomic for D11S1318, carried a small de novo dup(11)(p15.5p15.5), resulting from unequal recombination at paternal meiosis I. The duplicated region involves only IC1 and spares IC2/LIT1, as shown by fluorescent in situ hybridisation (FISH) mapping of the proximal duplication breakpoint within the amino-terminal part of KvLQT1. CONCLUSIONS: An additional patient with Wolf-Hirschorn syndrome was shown by FISH studies to carry a der(4)t(4;11)(p16.3;p15.4), contributed by a balanced translocation father. Interestingly, refined breakpoint mapping on 11p and the critical regions on the partner 21q and 4p chromosomal regions suggested that both translocations affecting 11p15.4 are mediated by segmental duplications. These findings of chromosomal rearrangements affecting 11p15.5-15.4 provide a tool to further dissect the genomics of the BWS region and the pathogenesis of this imprinting disorder.

EEG findings during "paroxysmal hemiplegia" in a patient with GLUT1-deficiency.

BACKGROUND: A growing number of studies have disclosed the myriad of features that can suggest the diagnosis of a Glucose-transporter-1 deficiency (GLUT1D). The occurrence of paroxysmal movement disorders such as exercise-induced dystonia and non-kinesigenic dyskinesia, received considerable emphasis, while limited attention has been paid to other paroxysmal phenomena, as transitory neurological disorders. These paroxysmal events are roughly and variably described as limb weakness, hemiparesis or ataxia. Their EEG correlate has been never documented. CASE DESCRIPTION AND CONCLUSION: We report the EEG pattern characterizing two acute episodes of paroxysmal paresis with confusion and aphasia, in a girl with GLUT1D. The EEG picture is characterized by a clear-cut contralateral EEG slowing, similar to what is observed in Alternating Hemiplegia of Childhood and Hemiplegic Migraine attacks. In our patient the paroxysmal events were responsive to a ketogenic diet.

Benign nocturnal alternating hemiplegia of childhood: six patients and long-term follow-up.

Benign familial nocturnal alternating hemiplegia of childhood refers to recurrent attacks of hemiplegia arising from sleep, described in young children without neurologic or mental impairment. It is probably migraine related. The authors report two unrelated patients with nocturnal attacks starting at 22 and 31 months, followed by daytime episodes in one. The authors confirm the benign course of this disorder. It is distinct from the classic malignant form of alternating hemiplegia of childhood.

Felbamate in therapy-resistant epilepsy: an Italian experience. Felbamate Italian Study Group.

We evaluated the use of felbamate in 379 adults and children with refractory epilepsies in an open-label, compassionate clinical use setting. Prior to the termination of the program, because of reports of aplastic anemia, 351 patients had completed 2 months of treatment with felbamate at a dose of 2400-3600 mg/day for adults or 30-45 mg/kg/day for children. Of the 246 patients who had a diagnosis of therapy-refractory localization-related epilepsy with or without secondary generalization, 52% (126/246) achieved a seizure reduction of 50% or more, including 10% (25/246) who became seizure free. There was no difference in response rate between adults and children. Of the 80 patients who had a diagnosis of Lennox-Gastaut syndrome (LGS), 60% (48/80) achieved a seizure reduction of 50% or more, including 6% (5/80) who became seizure free. Of the 25 patients with a diagnosis of generalized epilepsy (other than LGS) or undetermined epilepsy whether focal or generalized, 60% (15/25) achieved a seizure reduction of 50% or more, including 12% (3/24) who became seizure free. The results of this uncontrolled study suggest that felbamate could be useful in patients with epilepsies which are refractory to other antiepileptic drugs after careful risk-benefit assessment and consideration of all circumstances involved.

Symmetrical bithalamic hyperdensities in asphyxiated full-term newborns: an early indicator of status marmoratus.

Three severely asphyxiated full-term newborns showed tomographic findings of bilateral symmetrical hyperdensities restricted to the thalamic region. All these patients had a strikingly similar poor neurological outcome characterized by dystonia, severe mental retardation and acquired microcephaly. We presume that these bithalamic hyperdensities could be an early predictor of the later status marmoratus.

Tuberous sclerosis associated with partial gigantism in a child.

The authors report a case of a six-year-old boy with seizures, mental retardation and some classic features of tuberous sclerosis, i.e., cutaneous hypomelanotic macules, poliosis, cyst-like lesions of the right upper limb and cerebral calcifications. From birth he showed partial gigantism of the first two fingers of the right hand associated with an arteriovenous malformation of the ulnar artery and agenesis of the radial artery. The EEG and CT scan studies are also reported. The occurrence of two dysgenetic disorders in one patient as a manifestation of disturbed embryogenesis at a very early stage of development is discussed.

Minipolymyoclonus in congenital nemaline myopathy: a nonspecific clinical marker of neurogenic dysfunction.

The authors report a seven-month-old boy with severe hypotonia, poor spontaneous movements, breathing difficulties and recurrent respiratory infections, dysmorphisms and a peculiar movement disorder: minipolymyoclonus (MPM), previously reported only in spinal muscular atrophies. MPM is characterized by nonrhythmic myoclonic jerks associated with a rhythmic tremor of the extended fingers polygraphically detected. A muscle biopsy showed pathological changes typical of congenital nemaline myopathy (CNM). The relationship between MPM and CNM may be explained on the presumptive basis of the "neurogenic" nature of this congenital myopathy or by the non-specificity of this clinical sign.

Tuberous sclerosis and Down syndrome: a casual association?

This paper reports on the clinical, neurophysiological and neuroradiological characteristics of a patient with Down syndrome unusually associated with tuberous sclerosis. In particular, epilepsy is investigated in detail and its polygraphic study and etiopathological factors are discussed. The most interesting findings are those related to the presence of a structural abnormality of the rolandic-parietal cortex, bilaterally, in the form of pachygyria.

Acute measles encephalitis of the delayed type in an immunosuppressed child.

The authors described a case of an immunosuppressed child with acute measles encephalitis of the delayed type (AMED). The authors also discussed the relationship between the AMED, epilepsia partialis continua and the neuroradiological picture, in which bilateral putaminal lucency was evident.

Irreversible respiratory failure in an achondroplastic child: the importance of an early cervicomedullary decompression, and a review of the literature.

The authors report the case of a girl with achondroplasia suffering from a progressively worsening hypotonic quadriparesis. CT scan showed slight dilatation of ventricular and subarachnoid spaces, with well-defined evidence of cortical sulci and gyri. This aspect was compatible with the diagnosis of macrocrania and megalencephaly (CP being 51 cm). The foramen magnum was narrowed, the transverse diameter measuring 15 mm and the 50th percentile being, for age, 26 mm. Somatosensory evoked potentials (SEPs) revealed bilaterally prolonged interpeak latencies Erb-N13, slowing of central conduction time N13-N20 from right median nerve stimulation, and block from left median nerve. The suspicion of cervicomedullary compression was confirmed by MRI, showing a very marked stenosis with compression exerted by the odontoid process. Further, a stenotic cervical canal and optic nerves verticalization were manifest. The patient underwent neurosurgical decompression by suboccipital craniectomy and cervical-C1 laminectomy. In spite of treatment, both neurologic and respiratory problems (rapid, shallow and almost abdominal breathing) were unchanged. The girl died 4 1/2 months later. The authors emphasize the important role of SEPs in detection of cervicomedullary compression in achondroplastic children and also stress the necessity of an early surgical treatment as the only condition for possible clinical improvement and/or full recovery.

Kojewnikow's Epilepsia Partialis Continua: two cases associated with striatal necrosis.

The authors report two cases of children suffering from Epilepsia Partialis Continua (EPC). The first case concerned a boy primarily affected by abdominal neuroblastoma and secondarily by bilateral EPC; "pallidal posture" was the prominent clinical feature. An acute measles encephalitis was diagnosed and the CT scan showed necrosis of the putamina. The second case concerned a girl suffering from increased intracranial pressure due to suprasellar craniopharyngioma. Seven days after intervention, Diabetes Insipidus and EPC appeared. Enlargement of rolandic and sylvian spaces and lacunar necrosis of the putamen on the left side were also evident on the CT scan. The authors emphasize the significance of occasional metabolic disturbances, especially natremia, in the development of EPC.

Epilepsia partialis continua in a case of MELAS: clinical and neurophysiological study.

There are few reports in the literature dealing with the association between mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) and epilepsia partialis continua (EPC) in children. We report the case of a child presenting with numerous stroke-like episodes associated with EPC which, despite therapy, were not controlled and aggravated the clinical condition of our patient. We present the neuroradiological, biochemical, genetic and muscle biopsy findings, and EEG characteristics, with attention to polygraphic recordings which were done during wake and sleep periods. We consider the correlation with other possible etiological factors relating to EPC and in particular coinvolvement of the basal ganglia as a cause of EPC in our patient.

Giant somatosensory evoked potentials and pathophysiology of hyperekplexia. Neurophysiological study of one patient.

EEG during wakefulness and sleep and somatosensory evoked potentials from the median nerve were recorded in a 3 year-old boy with hyperekplexia and his close relatives (parents and two sisters). Centro-temporal spikes during sleep were found in the patient and in the older sister, while somatosensory evoked potentials, in the patient, showed abnormally high amplitude over the centroparietal regions. Pathophysiological mechanisms of hyperekplexia are discussed and the existence of symptomatic forms is suggested.

Partial seizures and migraine.

Epilepsy and migraine, despite some common features, have quite different pathophysiological mechanisms. Studies carried out on large population samples have shown that the relationships between migraine and epilepsy may be of the following type: associated attacks, with migraine and seizures occurring quite independently of one another; combined attacks, with the two types of attacks succeeding one another in time; basilar artery migraine with seizures and marked EEG abnormalities; benign epilepsies with occipital discharges, migraine and intercalated seizures. We report four cases of particular interest.