Missense variants in the N-terminal domain of the A isoform of FHF2/FGF13 cause an X-linked developmental and epileptic encephalopathy.

Fibroblast growth factor homologous factors (FHFs) are intracellular proteins which regulate voltage-gated sodium (Nav) channels in the brain and other tissues. FHF dysfunction has been linked to neurological disorders including epilepsy. Here, we describe two sibling pairs and three unrelated males who presented in infancy with intractable focal seizures and severe developmental delay. Whole-exome sequencing identified hemi- and heterozygous variants in the N-terminal domain of the A isoform of FHF2 (FHF2A). The X-linked FHF2 gene (also known as FGF13) has alternative first exons which produce multiple protein isoforms that differ in their N-terminal sequence. The variants were located at highly conserved residues in the FHF2A inactivation particle that competes with the intrinsic fast inactivation mechanism of Nav channels. Functional characterization of mutant FHF2A co-expressed with wild-type Nav1.6 (SCN8A) revealed that mutant FHF2A proteins lost the ability to induce rapid-onset, long-term blockade of the channel while retaining pro-excitatory properties. These gain-of-function effects are likely to increase neuronal excitability consistent with the epileptic potential of FHF2 variants. Our findings demonstrate that FHF2 variants are a cause of infantile-onset developmental and epileptic encephalopathy and underline the critical role of the FHF2A isoform in regulating Nav channel function.

Lazarus Syndrome - Challenges Created by Pediatric Autoresuscitation.

ABSTRACT: Pediatric autoresuscitation is extremely rare, with only 4 documented cases in the literature. The longest recorded time between stopping cardio pulmonary resuscitation (CPR) and return of spontaneous circulation is 2 minutes. We report a previously well 18-month-old who attended the emergency department after an unexplained cardiac arrest. After 10 cycles of CPR, resuscitation was stopped; 6 minutes later, the patient had a return of spontaneous circulation and was transferred to the pediatric intensive care unit. The patient remains alive but with significant neurological impairment. There are a variety of theories regarding the pathology of pediatric autoresuscitation. The most commonly accepted model is that there is a degree of autopositive end-expiratory pressure impending venous return as a consequence of vigorous ventilation during CPR. This case challenges clinicians to reassess our current definition of death and reaffirms the need for clearer guidelines surrounding the certification of death.

Surgical management of raised intracranial pressure secondary to otogenic infection and venous sinus thrombosis.

PURPOSE: This study reviews paediatric patients with raised intracranial pressure as a result of venous sinus thrombosis secondary to otogenic mastoiditis, requiring admission to the paediatric neuroscience centre at the University Hospital Wales, Cardiff. The consensus regarding the management of otogenic hydrocephalus in the published literature is inconsistent, with a trend towards conservative over surgical management. We reviewed our management of this condition over a 9-year period especially with regard to ventriculo-peritoneal (VP) shunting. METHODS: Analysis of a prospectively collected database of paediatric surgical patients was analysed and patients diagnosed with otogenic hydrocephalus from November 2010 to August 2018 were identified. Our data was compared with the published literature on this condition. RESULTS: Eleven children, 7 males and 4 females, were diagnosed with otogenic hydrocephalus over the 9-year period. Five (45.5%) required VP shunt insertion to manage their intracranial pressure and protect their vision. The remaining six patients (54.5%) were managed medically. CONCLUSIONS: When children with mastoiditis and venous sinus thrombosis progress to having symptoms or signs of raised intracranial pressure, they should ideally be managed within a neuroscience centre. Of those children, almost half will need permanent cerebrospinal fluid diversion to protect their sight.

Benign childhood epilepsy with centrotemporal spikes (BECTS) and developmental co-ordination disorder.

BACKGROUND: Benign epilepsy with centro-temporal spikes (BECTS) is a common childhood epilepsy syndrome also known as Rolandic Epilepsy (RE). Neurocognitive phenotypes have been described with greater focus on attention, reading and language domains but there have been far fewer studies focusing on motor functioning. This study included measures of motor, language and cognition in order to investigate the range, degree and pattern of difficulties associated with BECTS in a case series of children, but with a particular emphasis on motor skills. METHOD: Twenty-one children aged between 8 and 16years with a diagnosis of BECTS were asked to complete standardized assessments for language, cognition, motor functioning and handwriting. RESULTS: When measuring across language, cognitive and motor domains, 19 (90.48%) of the twenty-one children with a diagnosis of BECTS showed some difficulties on at least one area of functioning using standardized assessment tests. Of particular note nearly half (47.62%) of the children had some difficulties in one or more areas of motor functioning. DISCUSSION: Children with BECTS have a heterogeneous pattern of neurocognitive impairments. The presence of motor difficulties (DCD) should be considered in all children routinely seen in clinical settings with BECTS and included in any screening processes.

Pathogenic copy number variants and SCN1A mutations in patients with intellectual disability and childhood-onset epilepsy.

BACKGROUND: Copy number variants (CNVs) have been linked to neurodevelopmental disorders such as intellectual disability (ID), autism, epilepsy and psychiatric disease. There are few studies of CNVs in patients with both ID and epilepsy. METHODS: We evaluated the range of rare CNVs found in 80 Welsh patients with ID or developmental delay (DD), and childhood-onset epilepsy. We performed molecular cytogenetic testing by single nucleotide polymorphism array or microarray-based comparative genome hybridisation. RESULTS: 8.8 % (7/80) of the patients had at least one rare CNVs that was considered to be pathogenic or likely pathogenic. The CNVs involved known disease genes (EHMT1, MBD5 and SCN1A) and imbalances in genomic regions associated with neurodevelopmental disorders (16p11.2, 16p13.11 and 2q13). Prompted by the observation of two deletions disrupting SCN1A we undertook further testing of this gene in selected patients. This led to the identification of four pathogenic SCN1A mutations in our cohort. CONCLUSIONS: We identified five rare de novo deletions and confirmed the clinical utility of array analysis in patients with ID/DD and childhood-onset epilepsy. This report adds to our clinical understanding of these rare genomic disorders and highlights SCN1A mutations as a cause of ID and epilepsy, which can easily be overlooked in adults.

Resting-state oscillatory dynamics in sensorimotor cortex in benign epilepsy with centro-temporal spikes and typical brain development.

Benign Epilepsy with Centro-Temporal Spikes (BECTS) is a common childhood epilepsy associated with deficits in several neurocognitive domains. Neurophysiological studies in BECTS often focus on centro-temporal spikes, but these correlate poorly with morphology and cognitive impairments. To better understand the neural profile of BECTS, we studied background brain oscillations, thought to be integrally involved in neural network communication, in sensorimotor areas. We used independent component analysis of temporally correlated sources on magnetoencephalography recordings to assess sensorimotor resting-state network activity in BECTS patients and typically developing controls. We also investigated the variability of oscillatory characteristics within focal primary motor cortex (M1), localized with a separate finger abduction task. We hypothesized that background oscillations would differ between patients and controls in the sensorimotor network but not elsewhere, especially in the beta band (13-30 Hz) because of its role in network communication and motor processing. The results support our hypothesis: in the sensorimotor network, patients had a greater variability in oscillatory amplitude compared to controls, whereas there was no difference in the visual network. Network measures did not correlate with age. The coefficient of variation of resting M1 peak frequency correlated negatively with age in the beta band only, and was greater than average for a number of patients. Our results point toward a "disorganized" functional sensorimotor network in BECTS, supporting a neurodevelopmental delay in sensorimotor cortex. Our findings further suggest that investigating the variability of oscillatory peak frequency may be a useful tool to investigate deficits of disorganization in neurodevelopmental disorders.

Long-term outcome of paediatric-onset multiple sclerosis: a population-based study.

BACKGROUND: Age of onset of multiple sclerosis (MS) peaks in the 3rd and 4th decades and is rarely less than 18. Robust longitudinal studies in paediatric-onset MS (POMS) are limited, and a clearer understanding of outcome could optimise management strategies. METHODS: Patients with disease onset <18 years were identified from a prospective population-based register. Clinical features including presenting symptoms, time to Expanded Disability Status Scale (EDSS) 4.0, 6.0 and 8.0 and onset of secondary progression were compared with patients with adult-onset MS (AOMS). RESULTS: 111 POMS patients were identified from a cohort of 2068. No significant differences in sex ratio, familial recurrence, relapse rate, ethnicity or clinical symptoms at presentation were identified between POMS and AOMS. However, interval to second relapse was longer (5 vs 2.6 years, p=0.04) and primary progressive disease was less common (0.9% vs 8.5%, p=0.003) in POMS than in AOMS. POMS patients also took longer to develop secondary progressive disease (32 vs 18 years, p=0.0001) and to reach disability milestones (EDSS 4.0, 23.8 vs 15.5 years, p<0.0001; EDSS 6.0, 30.8 vs 20.4 years, p<0.0001; EDSS 8.0, 44.7 vs 39 years, p=0.02), but did so between 7.0 and 12 years younger than in AOMS. CONCLUSIONS: 5.4% of patients with MS have POMS (2.7% <16 years; 0.3% <10 years) and have distinct phenotypic characteristics in early disease. Furthermore, while patients with POMS take longer to reach disability milestones, they do so at a younger age than their adult counterparts and could be considered to have a poorer prognosis. Management strategies for these patients should take account of these data.

Leukoencephalopathy with thalamus and brainstem involvement and high lactate 'LTBL' caused by EARS2 mutations.

In the large group of genetically undetermined infantile-onset mitochondrial encephalopathies, multiple defects of mitochondrial DNA-related respiratory-chain complexes constitute a frequent biochemical signature. In order to identify responsible genes, we used exome-next-generation sequencing in a selected cohort of patients with this biochemical signature. In an isolated patient, we found two mutant alleles for EARS2, the gene encoding mitochondrial glutamyl-tRNA synthetase. The brain magnetic resonance imaging of this patient was hallmarked by extensive symmetrical cerebral white matter abnormalities sparing the periventricular rim and symmetrical signal abnormalities of the thalami, midbrain, pons, medulla oblongata and cerebellar white matter. Proton magnetic resonance spectroscopy showed increased lactate. We matched this magnetic resonance imaging pattern with that of a cohort of 11 previously selected unrelated cases. We found mutations in the EARS2 gene in all. Subsequent detailed clinical and magnetic resonance imaging based phenotyping revealed two distinct groups: mild and severe. All 12 patients shared an infantile onset and rapidly progressive disease with severe magnetic resonance imaging abnormalities and increased lactate in body fluids and proton magnetic resonance spectroscopy. Patients in the 'mild' group partially recovered and regained milestones in the following years with striking magnetic resonance imaging improvement and declining lactate levels, whereas those of the 'severe' group were characterized by clinical stagnation, brain atrophy on magnetic resonance imaging and persistent lactate increases. This new neurological disease, early-onset leukoencephalopathy with thalamus and brainstem involvement and high lactate, is hallmarked by unique magnetic resonance imaging features, defined by a peculiar biphasic clinical course and caused by mutations in a single gene, EARS2, expanding the list of medically relevant defects of mitochondrial DNA translation.

Ipsilateral cortical motor desynchronisation is reduced in Benign Epilepsy with Centro-Temporal Spikes.

OBJECTIVE: Magnetoencephalography (MEG) and a simple motor paradigm were used to study induced sensorimotor responses and their relationship to motor skills in children diagnosed with Benign Epilepsy with Centro-Temporal Spikes (BECTS). METHODS: Twenty-one children with BECTS and 15 age-matched controls completed a finger abduction task in MEG; movement-related oscillatory responses were derived and contrasted between groups. A subset of children also completed psycho-behavioural assessments. Regression analyses explored the relationship of MEG responses to manual dexterity performance, and dependence upon clinical characteristics. RESULTS: In children with BECTS, manual dexterity was below the population mean (p=.002) and three showed severe impairment. Our main significant finding was of reduced ipsilateral movement related beta desynchrony (MRBDi) in BECTS relative to the control group (p=.03) and predicted by epileptic seizure recency (p=.02), but not age, medication status, or duration of epilepsy. Laterality scores across the entire cohort indicated that less lateralised MRBD predicted better manual dexterity (p=.04). CONCLUSIONS: Altered movement-related oscillatory responses in ipsilateral motor cortex were associated with motor skill deficits in children with BECTS. These changes were more marked in those with more recent seizures. SIGNIFICANCE: These findings may reflect differences in inter-hemispheric interactions during motor control in BECTS.