Publications by authors named "Johann te Water Naude"

14 Publications

  • Page 1 of 1

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

Am J Hum Genet 2021 01 26;108(1):176-185. Epub 2020 Nov 26.

Neurology and Molecular Neuroscience Research, Institute of Life Science, Swansea University Medical School, Swansea University, Swansea SA2 8PP, UK; Kids Neuroscience Centre, Kids Research, Children Hospital at Westmead, Sydney, NSW 2145, Australia; Brain and Mind Centre, Faculty of Medicine and Health, University of Sydney, NSW 2050, Australia.

Fibroblast growth factor homologous factors (FHFs) are intracellular proteins which regulate voltage-gated sodium (Na) 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 Na channels. Functional characterization of mutant FHF2A co-expressed with wild-type Na1.6 (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 Na channel function.
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http://dx.doi.org/10.1016/j.ajhg.2020.10.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7820623PMC
January 2021

Focal segmental glomerulosclerosis and mild intellectual disability in a patient with a novel de novo truncating TRIM8 mutation.

Eur J Med Genet 2020 Sep 10;63(9):103972. Epub 2020 Jun 10.

Division of Cancer and Genetics, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK; Institute of Medical Genetics, University Hospital of Wales, Heath Park, Cardiff, CF14 4XW, UK. Electronic address:

Mutations in the TRIM8 gene have been described in patients with severe developmental delay, intellectual disability and epilepsy. Only six patients have been described to date. All the previous mutations were truncating variants clustered in the C-terminus of the protein. A previous patient with TRIM8-related epileptic encephalopathy was reported to have nephrotic syndrome. Here we describe the clinical, radiological and histological features of an 8-year-old male patient with a TRIM8 mutation who, in contrast to previous patients, had only mild intellectual disability and well-controlled epilepsy. The patient was found to have proteinuria at 2 years of age. Renal biopsy findings were suggestive of focal segmental glomerulosclerosis. His kidney function declined and peritoneal dialysis was started at 5 years of age. He underwent renal transplant at 7 years of age. Trio-based whole genome sequencing identified a novel de novo heterozygous frameshift mutation in TRIM8 (NM_030912.2) c.1198_1220del, p.(Tyr400ArgfsTer2). This patient is further evidence that TRIM8 mutations cause a syndrome with both neurological and renal features. Our findings suggest the spectrum of TRIM8-related disease may be wider than previously thought with the possibility of milder neurodevelopmental problems and/or a more severe, progressive renal phenotype. We highlight the need for proteinuria screening in patients with TRIM8 mutations.
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http://dx.doi.org/10.1016/j.ejmg.2020.103972DOI Listing
September 2020

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

Childs Nerv Syst 2020 02 23;36(2):349-351. Epub 2019 Aug 23.

Department of Paediatric Neurosurgery, University Hospital of Wales, Cardiff, UK.

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.
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http://dx.doi.org/10.1007/s00381-019-04353-3DOI Listing
February 2020

Lazarus Syndrome - Challenges Created by Pediatric Autoresuscitation.

Pediatr Emerg Care 2021 Apr;37(4):e210-e211

Division of Population Medicine, School of Medicine, Cardiff University, Cardiff, Wales, United Kingdom.

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.
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http://dx.doi.org/10.1097/PEC.0000000000001593DOI Listing
April 2021

Integrating glycomics and genomics uncovers SLC10A7 as essential factor for bone mineralization by regulating post-Golgi protein transport and glycosylation.

Hum Mol Genet 2018 09;27(17):3029-3045

Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.

Genomics methodologies have significantly improved elucidation of Mendelian disorders. The combination with high-throughput functional-omics technologies potentiates the identification and confirmation of causative genetic variants, especially in singleton families of recessive inheritance. In a cohort of 99 individuals with abnormal Golgi glycosylation, 47 of which being unsolved, glycomics profiling was performed of total plasma glycoproteins. Combination with whole-exome sequencing in 31 cases revealed a known genetic defect in 15 individuals. To identify additional genetic factors, hierarchical clustering of the plasma glycomics data was done, which indicated a subgroup of four patients that shared a unique glycomics signature of hybrid type N-glycans. In two siblings, compound heterozygous mutations were found in SLC10A7, a gene of unknown function in human. These included a missense mutation that disrupted transmembrane domain 4 and a mutation in a splice acceptor site resulting in skipping of exon 9. The two other individuals showed a complete loss of SLC10A7 mRNA. The patients' phenotype consisted of amelogenesis imperfecta, skeletal dysplasia, and decreased bone mineral density compatible with osteoporosis. The patients' phenotype was mirrored in SLC10A7 deficient zebrafish. Furthermore, alizarin red staining of calcium deposits in zebrafish morphants showed a strong reduction in bone mineralization. Cell biology studies in fibroblasts of affected individuals showed intracellular mislocalization of glycoproteins and a defect in post-Golgi transport of glycoproteins to the cell membrane. In contrast to yeast, human SLC10A7 localized to the Golgi. Our combined data indicate an important role for SLC10A7 in bone mineralization and transport of glycoproteins to the extracellular matrix.
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http://dx.doi.org/10.1093/hmg/ddy213DOI Listing
September 2018

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

Epilepsy Behav 2017 07 7;72:122-126. Epub 2017 Jun 7.

Welsh Epilepsy Centre, University Hospital of Wales, Cardiff, UK. Electronic address:

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.
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http://dx.doi.org/10.1016/j.yebeh.2017.04.014DOI Listing
July 2017

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

BMC Med Genet 2016 04 26;17(1):34. Epub 2016 Apr 26.

MRC Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, CF24 4HQ, UK.

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.
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http://dx.doi.org/10.1186/s12881-016-0294-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4845474PMC
April 2016

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

Clin Neurophysiol 2016 Feb 14;127(2):1147-1156. Epub 2015 Oct 14.

Cardiff University Brain Research Imaging Centre, Cardiff University, Cardiff, UK; Welsh Epilepsy Centre, University Hospital of Wales, Cardiff, UK.

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.
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http://dx.doi.org/10.1016/j.clinph.2015.08.020DOI Listing
February 2016

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

Hum Brain Mapp 2015 Oct 14;36(10):3935-49. Epub 2015 Jul 14.

CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom.

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.
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http://dx.doi.org/10.1002/hbm.22888DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6869151PMC
October 2015

Characterization of human disease phenotypes associated with mutations in TREX1, RNASEH2A, RNASEH2B, RNASEH2C, SAMHD1, ADAR, and IFIH1.

Am J Med Genet A 2015 Feb 16;167A(2):296-312. Epub 2015 Jan 16.

INSERM UMR 1163, Laboratory of Neurogenetics and Neuroinflammation, Paris Descartes - Sorbonne Paris Cité University, Institut Imagine, Hôpital Necker, Paris, France; Manchester Centre for Genomic Medicine, Institute of Human Development, Faculty of Medical and Human Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK.

Aicardi-Goutières syndrome is an inflammatory disease occurring due to mutations in any of TREX1, RNASEH2A, RNASEH2B, RNASEH2C, SAMHD1, ADAR or IFIH1. We report on 374 patients from 299 families with mutations in these seven genes. Most patients conformed to one of two fairly stereotyped clinical profiles; either exhibiting an in utero disease-onset (74 patients; 22.8% of all patients where data were available), or a post-natal presentation, usually within the first year of life (223 patients; 68.6%), characterized by a sub-acute encephalopathy and a loss of previously acquired skills. Other clinically distinct phenotypes were also observed; particularly, bilateral striatal necrosis (13 patients; 3.6%) and non-syndromic spastic paraparesis (12 patients; 3.4%). We recorded 69 deaths (19.3% of patients with follow-up data). Of 285 patients for whom data were available, 210 (73.7%) were profoundly disabled, with no useful motor, speech and intellectual function. Chilblains, glaucoma, hypothyroidism, cardiomyopathy, intracerebral vasculitis, peripheral neuropathy, bowel inflammation and systemic lupus erythematosus were seen frequently enough to be confirmed as real associations with the Aicardi-Goutieres syndrome phenotype. We observed a robust relationship between mutations in all seven genes with increased type I interferon activity in cerebrospinal fluid and serum, and the increased expression of interferon-stimulated gene transcripts in peripheral blood. We recorded a positive correlation between the level of cerebrospinal fluid interferon activity assayed within one year of disease presentation and the degree of subsequent disability. Interferon-stimulated gene transcripts remained high in most patients, indicating an ongoing disease process. On the basis of substantial morbidity and mortality, our data highlight the urgent need to define coherent treatment strategies for the phenotypes associated with mutations in the Aicardi-Goutières syndrome-related genes. Our findings also make it clear that a window of therapeutic opportunity exists relevant to the majority of affected patients and indicate that the assessment of type I interferon activity might serve as a useful biomarker in future clinical trials.
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http://dx.doi.org/10.1002/ajmg.a.36887DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4382202PMC
February 2015

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

J Neurol Neurosurg Psychiatry 2013 Feb 15;84(2):141-7. Epub 2012 Nov 15.

Institute of Psychological Medicine and Clinical Neuroscience, Cardiff University, University Hospital of Wales, Heath Park, Cardiff CF14 4XN, UK.

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.
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http://dx.doi.org/10.1136/jnnp-2012-303996DOI Listing
February 2013

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

Brain 2012 May 4;135(Pt 5):1387-94. Epub 2012 Apr 4.

VU University Medical Centre, De Boelelaan 1117, Amsterdam, The Netherlands.

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.
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http://dx.doi.org/10.1093/brain/aws070DOI Listing
May 2012

Neuromyelitis optica complicating autoimmune lymphoproliferative syndrome in a 4-year-old girl.

Br J Haematol 2011 Feb 25;152(3):247. Epub 2010 Nov 25.

Department of Paediatric Haematology/Oncology, Children's Hospital for Wales, CARDIFF, UK.

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http://dx.doi.org/10.1111/j.1365-2141.2010.08460.xDOI Listing
February 2011