ATP6V0C variants impair V-ATPase function causing a neurodevelopmental disorder often associated with epilepsy.

The vacuolar H+-ATPase is an enzymatic complex that functions in an ATP-dependent manner to pump protons across membranes and acidify organelles, thereby creating the proton/pH gradient required for membrane trafficking by several different types of transporters. We describe heterozygous point variants in ATP6V0C, encoding the c-subunit in the membrane bound integral domain of the vacuolar H+-ATPase, in 27 patients with neurodevelopmental abnormalities with or without epilepsy. Corpus callosum hypoplasia and cardiac abnormalities were also present in some patients. In silico modelling suggested that the patient variants interfere with the interactions between the ATP6V0C and ATP6V0A subunits during ATP hydrolysis. Consistent with decreased vacuolar H+-ATPase activity, functional analyses conducted in Saccharomyces cerevisiae revealed reduced LysoSensor fluorescence and reduced growth in media containing varying concentrations of CaCl2. Knockdown of ATP6V0C in Drosophila resulted in increased duration of seizure-like behaviour, and the expression of selected patient variants in Caenorhabditis elegans led to reduced growth, motor dysfunction and reduced lifespan. In summary, this study establishes ATP6V0C as an important disease gene, describes the clinical features of the associated neurodevelopmental disorder and provides insight into disease mechanisms.

Cognitive outcomes following epilepsy in infancy: A longitudinal community-based study.

OBJECTIVE: Onset of epilepsy before 2 years of age is associated with poor cognitive outcome; however, the natural course of the range of epilepsies that occur at this age is unknown. The aim of this prospective community-based study was to investigate the neuropsychological development of infants with newly diagnosed epilepsy longitudinally and to identify the clinical factors that predict long-term impairment. METHODS: Sixty-six infants <24 months of age were enrolled in the baseline phase of this study; 40 were seen again at 1-year follow-up and 40 at 3-year follow-up. Children underwent a neurological and neuropsychological assessment at each time point. RESULTS: More than 55% of children demonstrated impaired cognitive functioning at each assessment, with a similar percentage showing impaired memory and attention at 3-year follow-up. Cognitive scores obtained at each time point were correlated. More than 20 seizures/seizure clusters prior to assessment and an abnormal neurologic examination predicted poor cognitive functioning at baseline, whereas continuing seizures and baseline cognitive score predicted 3-year intelligence quotient (IQ)/cognitive score. SIGNIFICANCE: These findings demonstrate the following: (1) infants who are performing poorly at baseline continue to display impaired development at follow-up, (2) these children are delayed across a range of neuropsychological functions, and (3) a high number of seizures close to initial diagnosis and continuing seizures at follow-up independently predict cognitive impairment. These findings help to identify those infants with new-onset epilepsy who are most at risk for poor developmental outcome and suggest that multimodal interventions should be instituted early in the course of the disorder to improve outcomes.

ADCY5-related dyskinesia presenting as familial myoclonus-dystonia.

We describe a family with an autosomal dominant familial dyskinesia resembling myoclonus-dystonia associated with a novel missense mutation in ADCY5, found through whole-exome sequencing. A tiered analytical approach was used to analyse whole-exome sequencing data from an affected grandmother-granddaughter pair. Whole-exome sequencing identified 18,000 shared variants, of which 46 were non-synonymous changes not present in a local cohort of control exomes (n = 422). Further filtering based on predicted splicing effect, minor allele frequency in the 1000 Genomes Project and on phylogenetic conservation yielded 13 candidate variants, of which the heterozygous missense mutation c.3086T>G, p. M1029R in ADCY5 most closely matched the observed phenotype. This report illustrates the utility of whole-exome sequencing in cases of undiagnosed movement disorders with clear autosomal dominant inheritance. Moreover, ADCY5 mutations should be considered in cases with apparent myoclonus-dystonia, particularly where SCGE mutations have been excluded. ADCY5-related dyskinesia may manifest variable expressivity within a single family, and affected individuals may be initially diagnosed with differing neurological phenotypes.

Leukoencephalopathy with calcifications and cysts: a purely neurological disorder distinct from coats plus.

OBJECTIVE: With the identification of mutations in the conserved telomere maintenance component 1 (CTC1) gene as the cause of Coats plus (CP) disease, it has become evident that leukoencephalopathy with calcifications and cysts (LCC) is a distinct genetic entity. PATIENTS AND METHODS: A total of 15 patients with LCC were identified from our database of patients with intracranial calcification. The clinical and radiological features are described. RESULTS: The median age (range) at presentation was 10 months (range, 2 days-54 years). Of the 15 patients, 9 presented with epileptic seizures, 5 with motor abnormalities, and 1 with developmental delay. Motor abnormalities developed in 14 patients and cognitive problems in 13 patients. Dense calcification occurred in the basal ganglia, thalami, dentate nucleus, brain stem, deep gyri, deep white matter, and in a pericystic distribution. Diffuse leukoencephalopathy was present in all patients, and it was usually symmetrical involving periventricular, deep, and sometimes subcortical, regions. Cysts developed in the basal ganglia, thalamus, deep white matter, cerebellum, or brain stem. In unaffected areas, normal myelination was present. No patient demonstrated cerebral atrophy. CONCLUSION: LCC shares the neuroradiological features of CP. However, LCC is a purely neurological disorder distinguished genetically by the absence of mutations in CTC1. The molecular cause(s) of LCC has (have) not yet been determined.

A population-based study of newly diagnosed epilepsy in infants.

PURPOSE: Most published data on infants presenting with epilepsy originate from hospital/specialist clinic settings and may therefore not be representative of the general population. We carried out a population-based study to estimate the incidence of epilepsy onset in infants, to characterize the range of phenotypes and associated structural brain abnormalities, and to determine whether specific epilepsy diagnoses could be established at onset. METHODS: Children between 1 and 24 months of age with new-onset epilepsy were ascertained over 13 months from the residents in 15 boroughs of North London. Classification based on clinical information, electroencephalography (EEG), and neuroimaging data was undertaken independently by two pediatric neurologists. Neuroimages were reviewed by two neuroradiologists blinded to clinical details. KEY FINDINGS: A total of 57 children were enrolled giving an ascertainment-adjusted incidence of 70.1 (95% CI [56.3, 88.5])/100,000 children ≤ 2 years of age/year (ascertainment 76%). The incidence was highest among Asian children. An electroclinical syndrome was identified in 24 (42%) cases of which 21 were epileptic encephalopathies. Magnetic resonance (MR) images of 51 cases (89% of the total cohort) were reviewed. These demonstrated positive findings in 37 (72%) of 51 cases, of which 26 (51%) of 51 were etiologically relevant, and included developmental malformations in 11 (21%) of 51. SIGNIFICANCE: In a population setting infantile onset epilepsy presents mostly with complex phenotypes commonly associated with structural brain abnormalities. Routine MR imaging at presentation is therefore justified. However, identification of specific electroclinical syndromes remains difficult at onset.

An investigation into the relationship between vigabatrin, movement disorders, and brain magnetic resonance imaging abnormalities in children with infantile spasms.

AIM: We aimed to investigate the relationship between movement disorders, changes on brain magnetic resonance imaging (MRI), and vigabatrin therapy in children with infantile spasms. METHOD: Retrospective review and brain MRI analysis of children enrolled in the International Collaborative Infantile Spasms Study (ICISS) who developed a movement disorder on vigabatrin therapy. Comparisons were made with controls within ICISS who had no movement disorder. RESULTS: Ten of 124 infants had a movement disorder and in eight it had developed on vigabatrin therapy. Two had a movement disorder that resolved on dose-reduction of vigabatrin, one had improvement on withdrawing vigabatrin, two had resolution without any dose change, and in three it persisted despite vigabatrin withdrawal. The typical brain MRI changes associated with vigabatrin therapy were noted in two infants. Ten control infants were identified. Typical MRI changes noted with vigabatrin were noted in three controls. INTERPRETATION: It is possible that in two out of eight cases, vigabatrin was associated with the development of a movement disorder. In six out of eight cases a causal relationship was less plausible. The majority of infants treated with vigabatrin did not develop a movement disorder. MRI changes associated with vigabatrin do not appear to be specifically related to the movement disorder.

Childhood presentation of COL4A1 mutations.

AIM: To describe the clinical and radiological features of four new families with a childhood presentation of COL4A1 mutation. METHOD: We retrospectively reviewed the clinical presentation. Investigations included radiological findings and COL4A1 mutation analysis of the four cases. Affected family members were identified. COL4A1 mutation analysis was performed in all index cases and, where possible, in affected family members. RESULTS: The three male and one female index cases presented with recurrent childhood-onset stroke, infantile hemiplegia/spastic quadriplegia, and infantile spasms. Additional features such as congenital cataracts and anterior segment dysgenesis were present. Microcephaly and developmental delay/learning difficulties were present in three cases. Three cases had one or more family member affected in multiple generations, with a total of 11 such individuals identified. The clinical features showed a wide intrafamilial variation. Magnetic resonance imaging (MRI) showed bilateral white matter change in all cases, except in one mutation-positive family member. Unilateral or bilateral porencephaly was present in cases with infantile hemiplegia, and a diagnosis of clinical stroke was supported by the presence of intracerebral haemorrhage. The age at diagnosis was between 1 year and 6 years for the children with presentation in infancy and 12 months after stroke in a 14-year-old male. Three new pathogenic mutations were identified in the COL4A1 gene. INTERPRETATION: COL4A1 mutations can present in children with infantile hemiplegia/quadriplegia, stroke or epilepsy, and a motor disorder. The presence of eye features and white matter change on MRI in childhood can help point towards the diagnosis. Once the diagnosis is made, a careful search can identify affected family members.

Intrathecal baclofen pumps in the management of hypertonia in childhood: a UK and Ireland wide survey.

BACKGROUND: Intrathecal baclofen (ITB) is a useful treatment for hypertonia where non-invasive treatments have been ineffective or poorly tolerated. There is an absence of national guidance on selection criteria and a lack of literature regarding patient characteristics and treatment details for children and young people (CYP) receiving ITB therapy in the UK and Ireland. We aimed to gather patient and treatment characteristics for CYP receiving ITB in the UK and Ireland. METHODS: An electronic survey was sent to all paediatric ITB centres in the UK and Ireland. Anonymised data were returned between December 2019 and April 2020. CYP >16 years and those awaiting ITB pump removal were excluded from the dataset. RESULTS: 176 CYP were identified as receiving ITB therapy across the UK and Ireland. The majority of CYP with ITB pumps were non-ambulant (93%) with a diagnosis of cerebral palsy (79%). Median age of ITB insertion was 9 years; median current age was 14 years. 79% of CYP had significant spasticity, 55% had significant dystonia. The most commonly used ITB dosing modes were continuous (73%) and flexible (23%). CONCLUSIONS: ITB pumps were most frequently used for non-ambulant CYP with cerebral palsy and existence of spasticity and/or dystonia in the UK and Ireland. Most CYP were receiving a continuous dose of ITB. There is significant variation in the number of paediatric ITB pumps across UK and Ireland. There is a need for development of nationally accepted paediatric referral criteria and clinical standards for ITB use.

A randomized trial of classical and medium-chain triglyceride ketogenic diets in the treatment of childhood epilepsy.

PURPOSE: To conduct the first randomized trial on classical and medium-chain triglyceride (MCT) versions of the ketogenic diet, examining efficacy and tolerability after 3, 6, and 12 months. METHODS: One hundred forty-five children with intractable epilepsy were randomized to receive a classical or an MCT diet. Seizure frequency was assessed after 3, 6, and 12 months. Treatment withdrawals were documented. Tolerability was assessed by questionnaire, and blood ketone levels were measured. RESULTS: Of the 61 children who started a classical diet and the 64 who started an MCT diet, data from 94 were available for analysis: 45 classical and 49 MCT. After 3, 6, and 12 months there were no statistically significant differences in mean percentage of baseline seizures between the two groups (3 months: classical 66.5%, MCT 68.9%; 6 months: classical 48.5%, MCT 67.6%; 12 months: classical 40.8%, MCT 53.2%; all p > 0.05). There were no significant differences between groups in numbers achieving greater than 50% or 90% seizure reduction. Serum acetoacetate and beta-hydroxybutyrate levels at 3 and 6 months were significantly higher in children on the classical diet (p < 0.01); this was the case at 12 months for acetoacetate. There were no significant differences in tolerability except increased reports in the classical group of lack of energy after 3 months and vomiting after 12 months. DISCUSSION: This study has shown classical and MCT ketogenic diet protocols to be comparable in efficacy and tolerability; both ways of implementing the diet have their place in the treatment of childhood epilepsy.

The ketogenic diet for the treatment of childhood epilepsy: a randomised controlled trial.

BACKGROUND: The ketogenic diet has been widely and successfully used to treat children with drug-resistant epilepsy since the 1920s. The aim of this study was to test the efficacy of the ketogenic diet in a randomised controlled trial. METHODS: 145 children aged between 2 and 16 years who had at least daily seizures (or more than seven seizures per week), had failed to respond to at least two antiepileptic drugs, and had not been treated previously with the ketogenic diet participated in a randomised controlled trial of its efficacy to control seizures. Enrolment for the trial ran between December, 2001, and July, 2006. Children were seen at one of two hospital centres or a residential centre for young people with epilepsy. Children were randomly assigned to receive a ketogenic diet, either immediately or after a 3-month delay, with no other changes to treatment (control group). Neither the family nor investigators were blinded to the group assignment. Early withdrawals were recorded, and seizure frequency on the diet was assessed after 3 months and compared with that of the controls. The primary endpoint was a reduction in seizures; analysis was intention to treat. Tolerability of the diet was assessed by questionnaire at 3 months. The trial is registered with ClinicalTrials.gov, number NCT00564915. FINDINGS: 73 children were assigned to the ketogenic diet and 72 children to the control group. Data from 103 children were available for analysis: 54 on the ketogenic diet and 49 controls. Of those who did not complete the trial, 16 children did not receive their intervention, 16 did not provide adequate data, and ten withdrew from the treatment before the 3-month review, six because of intolerance. After 3 months, the mean percentage of baseline seizures was significantly lower in the diet group than in the controls (62.0%vs 136.9%, 75% decrease, 95% CI 42.4-107.4%; p<0.0001). 28 children (38%) in the diet group had greater than 50% seizure reduction compared with four (6%) controls (p<0.0001), and five children (7%) in the diet group had greater than 90% seizure reduction compared with no controls (p=0.0582). There was no significant difference in the efficacy of the treatment between symptomatic generalised or symptomatic focal syndromes. The most frequent side-effects reported at 3-month review were constipation, vomiting, lack of energy, and hunger. INTERPRETATION: The results from this trial of the ketogenic diet support its use in children with treatment-intractable epilepsy. FUNDING: HSA Charitable Trust; Smiths Charity; Scientific Hospital Supplies; Milk Development Council.

Multidisciplinary care of a paediatric patient with Gradenigo's syndrome.

A 10-year-old girl presented with signs and symptoms suggestive of Gradenigo's syndrome, a condition characterised by otorrhoea, diplopia due to abducens nerve palsy and pain in the region of the trigeminal nerve. This case examines the presentation of this condition, and the appropriate investigations. We also highlight the importance of the involvement of multiple specialities in discussing and devising a suitable management plan.

Successful treatment of two paediatric cases of anti-NMDA receptor encephalitis with cyclophosphamide: the need for early aggressive immunotherapy in tumour negative paediatric patients.

We describe the clinical course and treatment of three unrelated female patients ranging in age from 27 months to 14 years with anti-NMDA receptor encephalitis. The third case is reported as an addendum to the paper. None of the cases were paraneoplastic. All received initial immunotherapy consisting of steroids and IVIg, and two of them received 3 and 8 plasma exchanges respectively, without consistent or sustained clinical improvement. All three girls were then treated with monthly cycles of Cyclophosphamide. All had resolution of their movement disorder and a dramatic and sustained clinical improvement of their other symptoms in the domains of cognition, language and behaviour. The clinical improvement began after the first cycle in two and the second cycle in the third and continued with the subsequent cycles. None developed side-effects of treatment. In light of the recent review of the condition and our own clinical experience in the paediatric age group, we propose that second line immunotherapy should be considered early after failure of first line immunotherapy.

Interrater reliability of Engel, International League Against Epilepsy, and McHugh seizure outcome classifications following vagus nerve stimulator implantation.

OBJECT: Interrater reliability as measured by the kappa (κ) statistic is a widely used and valuable tool to measure the robustness of a scoring system. Seizure frequency reduction is a central outcome measure following vagus nerve stimulation (VNS). A specific VNS scoring system has been proposed by McHugh, but its interrater reliability has not been tested. The authors assessed its interrater reliability and compared it with that of the Engel and International League Against Epilepsy (ILAE) systems. METHODS: Using the Engel, ILAE, and McHugh scoring systems, 3 observers independently rated the medical records of children who had undergone vagus nerve stimulator implantation between January 2001 and April 2011 at the Southampton University Hospital. The interrater agreements were then calculated using the κ statistic. RESULTS: Interrater reliability for the McHugh scale (κ0.693) was very good and was superior to those of the Engel (κ0.464) and ILAE (κ0.491) systems for assessing outcome in patients undergoing VNS. CONCLUSIONS: The authors recommend considering the McHugh scoring system when assessing outcomes following VNS.

Very good inter-rater reliability of Engel and ILAE epilepsy surgery outcome classifications in a series of 76 patients.

The inter-rater reliability, expressed as kappa score, k, of the Engel and International League Against Epilepsy (ILAE) classifications of epilepsy surgery seizure outcome has not previously been evaluated. In a consecutive series of 76 patients (40 male; 25 children), 75 undergoing resective and 1 disconnective surgery at a mean age of 27.5 years (13 months-62 years), one observer classified 88% (n=67) and a second observer classified 87% (n=66) of patients as either Engel I or II (free from or rare disabling seizures) after a median follow up of 36 months (range 12-92 months); comparably, both observers classified 84% (n=64) as ILAE 1-3. Correlation for Engel versus ILAE for observer 1 was 0.933 (p<.0005) and for observer 2 was 0.931 (p<.0005). Both ILAE (k 0.81, 95% confidence intervals 0.69, 0.91) and Engel (k 0.77, 95% CI 0.65, 0.87) classifications have very acceptable inter-rater reliability as well as significant correlation.

Massive SCA7 expansion detected in a 7-month-old male with hypotonia, cardiomegaly, and renal compromise.

Infantile spinocerebellar ataxia type 7 (SCA7) is phenotypically different from the child-onset and adult-onset cases, presenting as a multisystem disorder associated with pathologically large CAG trinucleotide repeat sequences. We describe a case study of a male who presented at 5 months of age with marked motor delay, failure to thrive, and a patent ductus arteriosus. He later developed renal failure of uncertain aetiology. The infant became progressively hypotonic, and cardiac and renal function deteriorated further; he died at the age of 11 months of multisystem failure. Family history revealed a diagnosis of SCA7 in the infant's father, paternal grandfather, and aunt. DNA analysis confirmed an expanded trinucleotide repeat in the SCA7 locus of about 240 repeats, suggesting a diagnosis of infantile SCA7. Striking anticipation is seen in SCA7, particularly with paternal transmission. The underlying pathophysiological processes seem to involve alteration in transcriptional regulation and a selective neuronal vulnerability to the widely distributed abnormal protein product. This case report reviews the current literature relating to infantile SCA7 and raises awareness of this rare but important phenotype.