KCTD7-related progressive myoclonic epilepsy: Report of 42 cases and review of literature

OBJECTIVE

KCTD7-related progressive myoclonic epilepsy (PME) is a rare autosomal-recessive disorder. This study aimed to describe the clinical details and genetic variants in a large international cohort.

METHODS

Families with molecularly confirmed diagnoses of KCTD7-related PME were identified through international collaboration. Furthermore, a systematic review was done to identify previously reported cases. Salient demographic, epilepsy, treatment, genetic testing, electroencephalographic (EEG), and imaging-related variables were collected and summarized.

RESULTS

Forty-two patients (36 families) were included. The median age at first seizure was 14 months (interquartile range = 11.75-22.5). Myoclonic seizures were frequently the first seizure type noted (n = 18, 43.9%). EEG and brain magnetic resonance imaging findings were variable. Many patients exhibited delayed development with subsequent progressive regression (n = 16, 38.1%). Twenty-one cases with genetic testing available (55%) had previously reported variants in KCTD7, and 17 cases (45%) had novel variants in KCTD7 gene. Six patients died in the cohort (age range = 1.5-21 years). The systematic review identified 23 eligible studies and further identified 59 previously reported cases of KCTD7-related disorders from the literature. The phenotype for the majority of the reported cases was consistent with a PME (n = 52, 88%). Other reported phenotypes in the literature included opsoclonus myoclonus ataxia syndrome (n = 2), myoclonus dystonia (n = 2), and neuronal ceroid lipofuscinosis (n = 3). Eight published cases died over time (14%, age range = 3-18 years).

SIGNIFICANCE

This study cohort and systematic review consolidated the phenotypic spectrum and natural history of KCTD7-related disorders. Early onset drug-resistant epilepsy, relentless neuroregression, and severe neurological sequalae were common. Better understanding of the natural history may help future clinical trials.

Whole genome sequencing followed by functional analysis of genomic deletion encompassing ERCC8 and NDUFAF2 genes in a non-consanguineous Indian family reveals dysfunctional mitochondrial bioenergetics leading to infant mortality

Genomic investigations on an infant who presented with a putative mitochondrial disorder led to identification of compound heterozygous deletion with an overlapping region of ∼142 kb encompassing two nuclear encoded genes namely ERCC8 and NDUFAF2. Investigations on fetal-derived fibroblast culture demonstrated impaired bioenergetics and mitochondrial dysfunction, which explains the phenotype and observed infant mortality in the present study. The genetic findings from this study extended the utility of whole-genome sequencing as it led to development of a MLPA-based assay for carrier screening in the extended family and the prenatal testing aiding in the birth of two healthy children.

Stimulation-Induced Seizures in Children Undergoing Stereo-EEG Evaluation

PURPOSE

This study reports our center's initial experience with the use of low-frequency stimulation in provoking stimulation-induced seizures (SIS) in children with drug-resistant epilepsy undergoing stereo-EEG evaluations.

METHODS

This retrospective study enrolled children aged 2 to 18 years with drug-resistant focal epilepsy who underwent stereo-EEG evaluation and extraoperative direct electrical cortical stimulation to elicit seizures. The low-frequency stimulation parameters consisted of biphasic square waveforms at frequency of 1 Hz, pulse width 1 millisecond, current 1 to 3 mA, and train duration of 20 seconds. Various epilepsy-related, imaging, neurophysiology, and surgery-related variables were collected and summarized.

RESULTS

Fourteen children (mean age 13 years; 57.1% girls) were included, 10 of whom had unilateral stereo-EEG coverage. Cortical stimulation for provoking seizures was performed after a median of 5 days after electrode implantation. The median number of electrode-contacts stimulated per patient was 42. Four patients (28.6%) experienced habitual SIS (all extratemporal). The etiology in three patients was focal cortical dysplasia. Interictal high-frequency oscillations at electrode-contacts provoking SIS were observed in three cases (75%). Two of these individuals (50%) had class 1 International League Against Epilepsy seizure outcome at last follow-up, after the resection of the brain regions generating SIS.

CONCLUSIONS

Low-frequency (1-Hz) stimulation could provoke habitual SIS in nearly one-fourth of children with focal epilepsy undergoing stereo-EEG monitoring. This study provides a limited pediatric experience with the low-frequency cortical stimulation and SIS.

The 2022 International League Against Epilepsy Classification and Definition of Childhood Epilepsy Syndromes: An Update for Pediatricians

The 2017 classification of the epilepsies of International League Against Epilepsy (ILAE) defined three diagnostic levels, including seizure type, epilepsy type and epilepsy syndrome. Epilepsy syndromes have been recognized as distinct electroclinical entities well before the first ILAE classification of Epilepsies and Epilepsy Syndromes in 1985. A formally accepted classification of epilepsy syndromes was not available, and hence, the 2017-2021 Nosology and Definitions Task Force of ILAE was formulated. The ILAE position papers were published in 2022, which classified epilepsy syndromes into (1) syndromes with onset in neonates and infants (up to 2 years of age), (2) syndromes with onset in childhood, (3) syndromes that may begin at a variable age and (4) idiopathic generalized epilepsies. This classification recognized the concept of etiology-specific syndrome. These papers have addressed the specific clinical and laboratory features of epilepsy syndromes and specify the rationale for any significant changes in terminology or definition. This paper will review some pertinent changes and essential points relevant to pediatricians.

Drug-resistant focal epilepsy in a girl with SETD5-related intellectual disability

None.

Contralateral hippocampal sclerosis following functional hemispherectomy in children: A report of three cases

PURPOSE

Hippocampal Sclerosis (HS) may co-exist with temporal or extratemporal lesions (dual pathology) in children and is usually ipsilateral to the radiological lesion. Here were report three cases with extensive hemispheric cortical malformation and drug resistant epilepsy who had persistent seizures after functional hemispherectomy (FH) and developed contralateral HS after the surgery.

METHODS

This retrospective study enrolled children who underwent FH and developed contralateral HS after surgery. Their clinical, EEG, radiological and pathological data were reviewed and summarized.

RESULTS

Ninety-five children underwent FH during the study period; Three cases (3.2%) were eligible. They all had unilateral extensive hemispheric cortical malformation who underwent FH between 3 and 5 months of age with no clinical, EEG or radiological suggestion for involvement of contralateral hemisphere prior to FH. All three patients had persisting seizures after FH. Contralateral HS was detected between 2.2 to 3.7 years after FH in all three cases. Two of the patients showed pathogenic variants in GATOR1 pathway genes.

CONCLUSIONS

The genesis of contralateral HS in the reported patients remains unexplained. The presence and distribution of "second-hit" somatic mutations may play an important role in governing the seizure outcomes of epilepsy surgery in patients with apparently unilateral malformations of cortical development.

Diagnostic Yield of Five Minutes Compared to Three Minutes Hyperventilation During Electroencephalography in Children

Purpose: To investigate whether hyperventilation (HV) for 5 minutes increases the diagnostic yield of electroencephalography (EEG) compared to 3 minutes HV and to determine whether performing HV for 5 minutes is feasible and safe in children. Methods: Data were evaluated from 579 children aged less than 18 years, referred to EEG for epilepsy evaluation. Occurrence of seizures, HV induced interictal epileptiform discharges precipitation and potentiation and adverse events if any were noted during the first 3 minutes and last 2 minutes of HV separately. Results: 398 children (68.7%) completed 5 minutes HV. Seizures were precipitated during the first 3 minutes of HV in 2 children, and during the last 2 minutes in one more child. Inter-ictal EEG abnormalities were precipitated in the first 3 minutes of HV in 31 children, and during the last 2 min in 4 more children. All 398 children completed HV during the last 2 minutes successfully and no adverse events occurred during the last 2 minutes of HV. Conclusion: 33.33% of seizures and 11.5% of inter-ictal EEG abnormalities triggered by HV occurred during the last 2 min of HV. This finding supports the utility of prolonged hyperventilation for 5 minutes. Prolonged HV for 5 minutes increases the diagnostic yield of EEG in paediatric population and it is safe and feasible.

Serum Magnesium Levels in Children With and Without Migraine: A Cross-Sectional Study

OBJECTIVE

To study the association between serum magnesium level and migraine in children.

METHODS

This cross-sectional study enrolled children aged 5-18 years diagnosed with migraine, and age- and sex-matched controls without a headache disorder. International Classification of Headache Disorders 3 (ICHD-3) was used for the diagnosis of migraine. The association between serum magnesium level and migraine headache was analyzed.

RESULTS

A total of 35 children with migraine were enrolled with 35 control subjects. The median (IQR) serum magnesium levels were comparable among children with migraine and controls [2.0 (2.0,2.1) vs 2.2 (1.9, 2.2) mg/dL; P=0.23], respectively. In adolescent sub-group, median (IQR) serum magnesium levels were significantly low among the children with migraine as compared to those without migraine [2.0 (1.9, 2.1) vs 2.2 (2.0, 2.2 mg/dL); P<0.045].

CONCLUSION

We found a statistically significant association between low serum magnesium levels and the occurrence of migraine in adolescents, which may have treatment implications.

Favorable Response to "Memantine" in a Child with GRIN2B Epileptic Encephalopathy

GRIN2B is a gene encoding GluN2B subunit under the family of N-methyl D-aspartate (NMDA) receptors, which is responsible for neurogenesis and cognitive processes. The role of NMDA receptor antagonists like memantine is being explored for therapies in drug-resistant epilepsies. Here, we present a case of a 20-month-old boy who presented with refractory epileptic spasms. Upon failure of multiple antiepileptic drugs, he was started on oral memantine. There was a significant reduction in average seizure episodes by ∼80%. The use of memantine along with antiepileptic drug polytherapy has proved to be beneficial in our case. Our experience with memantine and favorable outcome opens up the scope of more research into the use of NMDA receptor antagonist as a drug option for refractory epilepsies with proven genetic mutation and hence improves the overall neurodevelopmental outcome and survival chance.

Favorable response to classic ketogenic diet in a child with anti-GAD 65 antibody mediated super refractory status epilepticus

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Autoimmune encephalitis is a disease condition which presents with refractory seizures in children requiring immunotherapy.

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KD is a non-pharmacological treatment modality used worldwide in people with drug-resistant epilepsy. It acts through many anti-inflammatory mechanisms leading to seizure control.

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This article highlights the use of adjuvant effect of ketogenic diet in anti GAD-65 antibody positive autoimmune encephalitis.

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It is the need of the hour to formulate treatment protocols incorporating newer treatment strategies including K_D.

Autoimmune encephalitis refers to a spectrum of inflammatory brain diseases which can present as drug-resistant seizures in children. Hereby, we report a case of anti-GAD-65 antibody encephalitis in a 7-year-old child who presented with superrefractory status epilepticus (SRSE). The traditional management with multiple anti-seizure medications at appropriate dosage and immunotherapy was tried despite which the child continued to have seizures. Hence the child was initiated on a classic ketogenic diet. He achieved ketosis within 48 h of diet initiation and there was a drastic reduction in the seizure frequency followed by a completed remission. Hence, this non-pharmacological intervention was an effective adjunct in achieving seizure control in our patient. A ketogenic diet has been sparingly used for the management of post-encephalitic epilepsy and autoimmune epilepsy. However, the data onthe effectiveness of the ketogenic diet in the management of autoimmune encephalitis is scarce. Starting K_D early in the disease course helped not only in seizure control but also preserved the cognitive and neurological well-being of the child.

Acute Encephalopathy with Biphasic Seizures and Late Reduced Diffusion Associated with Dengue Infection in a Child

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is a clinico-radiological syndrome in children secondary to viral or bacterial infections. The causes include viral (influenza, human herpes virus-6, adenovirus, rota) as well as bacterial infections. However, AESD with dengue infection has not been reported earlier. Here, we present an infant with dengue infection and AESD which recovered completely following treatment with intravenous human immunoglobulin therapy. A 9-month-old girl presented with seizures following fever and loose stools. Seizures recurred after 2 days of seizure-free interval. Cerebrospinal fluid analysis was not contributory. Dengue infection was confirmed by lab tests. Magnetic resonance imaging brain after the second seizure revealed diffusion restriction involving the bilateral frontal and parietal white matter, both hemispheres with a typical central perisylvian sparing lesion suggestive of AESD. This case report expands the reported spectrum of neurological manifestations of dengue infection.

Treatable Cause of Refractory Seizures in an Infant with a Novel Mutation

Pyridoxine-dependent epilepsy is a treatable cause of epilepsy, which is very well known. It is most commonly caused by mutations in ALDH7A1 and PNPO genes. A 5-month-old infant presented with refractory seizures. Magnetic resonance imaging (MRI) brain was normal. Clinical exome sequencing showed a novel mutation in PROSC gene. He responded very well to pyridoxine and has been seizure free since the beginning of the treatment. PROSC gene mutations have been recently described as a cause for pyridoxine-dependent epilepsy. Here, we describe a first case report of PROSC mutation from India with a rare genetic variant presenting as pyridoxine-dependent epilepsy.

An Atypical Presentation of Joubert Syndrome Due to a Novel Mutation in ZNF423 Gene

Joubert syndrome is a rare brain malformation characterized by the absence or underdevelopment of the cerebellar vermis. Infants with Joubert syndrome usually present with hypotonia, developmental delay, oculomotor apraxia, and respiratory abnormalities. Seizures in Joubert syndrome are not uncommon. Infantile spasms as presentation are hitherto unreported. Here we present a rare case of an 8-month-old infant diagnosed as Joubert syndrome with ZNF423 mutation who presented with West syndrome. Early diagnosis and appropriate management of the child effectively reduced the spasms.