Publications by authors named "Andy Cheuk-Him Ng"

Patients with TUBA1A pathogenic variants may present with complex brain malformation, intellectual disability, and epilepsy. The epilepsy phenotype is varied, ranging from mild to severe, with epileptic spasms and focal seizures being the most common seizure types. We report on an infant with a TUBA1A variant presenting with an evolving epileptic encephalopathy.

View Article and Find Full Text PDF

The electroencephalogram (EEG) is crucial for real-time brain physiology research in epilepsy. However, maternal care reliance limits its use in immature rodents. Our "pup-in-cup" setup overcomes this, enabling continuous, uninterrupted video-EEG/electromyogram (EMG) recordings in neonatal rats.

View Article and Find Full Text PDF

Patients with epileptic encephalopathy with spike wave activation in sleep (EE-SWAS) often display drug-resistant epilepsy. The activation of epileptic activity during sleep is associated temporally with neurocognitive impairment and causes a spectrum of disorders within the epilepsy-aphasia syndrome. The prognosis is dependent on promptness of treatment and etiology.

View Article and Find Full Text PDF

Pathogenic variants in genes encoding ion channels are causal for various pediatric and adult neurological conditions. In particular, several epilepsy syndromes have been identified to be caused by specific channelopathies. These encompass a spectrum from self-limited epilepsies to developmental and epileptic encephalopathies spanning genetic and acquired causes.

View Article and Find Full Text PDF

The devastating developmental and epileptic encephalopathy of infantile epileptic spasms syndrome (IESS) has numerous causes, including, but not limited to, brain injury, metabolic, and genetic conditions. Given the stereotyped electrophysiologic, age-dependent, and clinical findings, there likely exists one or more final common pathways in the development of IESS. The identity of this final common pathway is unknown, but it may represent a novel therapeutic target for infantile spasms.

View Article and Find Full Text PDF

Objective: Individuals with neurodevelopmental disorders such as global developmental delay (GDD) present both genotypic and phenotypic heterogeneity. This diversity has hampered developing of targeted interventions given the relative rarity of each individual genetic etiology. Novel approaches to clinical trials where distinct, but related diseases can be treated by a common drug, known as basket trials, which have shown benefits in oncology but have yet to be used in GDD.

View Article and Find Full Text PDF

Objective: Gain a better understanding of sex-specific differences in individuals with global developmental delay (GDD), with a focus on phenotypes and genotypes.

Methods: Using the Deciphering Developmental Disorders (DDD) dataset, we extracted phenotypic information from 6,588 individuals with GDD and then identified statistically significant variations in phenotypes and genotypes based on sex. We compared genes with pathogenic variants between sex and then performed gene network and molecular function enrichment analysis and gene expression profiling between sex.

View Article and Find Full Text PDF

We describe a unique clinical presentation of a child after the acute phase of herpes simplex virus 1 (HSV1) encephalitis. A 17-month-old boy first presented with HSV1 encephalitis and was promptly treated with antiviral medication. Seven months later, he was re-admitted for startle seizures.

View Article and Find Full Text PDF
Article Synopsis
  • Biallelic mutations in the SNORD118 gene are linked to a neurological condition called leukoencephalopathy with calcifications and cysts (LCC), affecting individuals' brains and leading to a range of symptoms.
  • A study identified 64 patients with LCC, showcasing a wide age range at disease onset and highlighting that most were compound heterozygotes for mutations in SNORD118, with many involving seven key nucleotides crucial for a specific RNA interaction.
  • The findings indicate that LCC is likely caused by a combination of severe and milder mutations impacting RNA processing, but there is no clear link between specific mutations and the age at which symptoms appear.
View Article and Find Full Text PDF

We report bi-allelic pathogenic HPDL variants as a cause of a progressive, pediatric-onset spastic movement disorder with variable clinical presentation. The single-exon gene HPDL encodes a protein of unknown function with sequence similarity to 4-hydroxyphenylpyruvate dioxygenase. Exome sequencing studies in 13 families revealed bi-allelic HPDL variants in each of the 17 individuals affected with this clinically heterogeneous autosomal-recessive neurological disorder.

View Article and Find Full Text PDF

Herein, we describe a case report of anti-NMDA receptor encephalitis characterized by a single generalized tonic-clonic seizure and predominantly psychiatric symptoms, persisting long after EEG abnormalities had resolved. We discuss common presentations of anti-NMDA receptor encephalitis and advocate for the inclusion of this disease entity in the differential diagnosis of patients presenting with one generalized tonic-clonic seizure and prominent psychiatric symptoms.

View Article and Find Full Text PDF

Aims: Mitochondrial function is coupled to metabolic and survival pathways through both direct signaling cascades and dynamic changes in mitochondrial morphology. For example, a hyperfused mitochondrial reticulum is activated upon cellular stress and is protective against cell death. As part of a genome-wide small inhibitory ribonucleic acid screen, we identified the central redox regulator, Keap1, as a novel regulator of mitochondrial morphology.

View Article and Find Full Text PDF

Multiple symmetric lipomatosis (MSL) is a mitochondrial disorder with impaired brown fat metabolism that has been associated with MERRF mutations in some, but not all, patients. We studied a sibling pair and an unrelated indiviadual who presented with MSL and neuropathy to determine the genetic etiology of this disorder in patients who did not carry the MSL-associated MERRF mutation. Whole-exome sequencing was performed on the siblings, and a rare, shared homozygous mutation in MFN2 (c.

View Article and Find Full Text PDF

PINK1/PARK6 and Parkin/PARK2 are amongst the most commonly mutated genes associated with recessive forms of familial Parkinson's disease. Recent evidence indicates that the proteins they encode, PINK1 and Parkin, function in the same pathway to mediate the selective autophagic clearance of dysfunctional mitochondria. Upon mitochondrial damage, PINK1 is stabilized on the outer mitochondrial membrane where it phosphorylates ubiquitin, generating a signal for the recruitment and activation of Parkin.

View Article and Find Full Text PDF

The tumorous imaginal disc 1 (TID1) protein localizes mainly to the mitochondrial compartment, wherein its function remains largely unknown. Here we report that TID1 regulates the steady-state homogeneity of the mitochondrial membrane potential (Δψ) and maintains the integrity of mitochondrial DNA (mtDNA). Silencing of TID1 with RNA interference leads to changes in the distribution of Δψ along the mitochondrial network, characterized by an increase in Δψ in focal regions.

View Article and Find Full Text PDF

The dynamics of mitochondria undergoing fusion and fragmentation govern many mitochondrial functions, including the regulation of cell survival. Although the machinery that catalyzes fusion and fragmentation has been well described, less is known about the signaling components that regulate these phenomena. We performed a genome-wide RNA interference (RNAi) screen and identified reactive oxygen species modulator 1 (ROMO1) as a redox-regulated protein required for mitochondrial fusion and normal cristae morphology.

View Article and Find Full Text PDF

Mitochondrial dysfunction is a hallmark of aging and numerous human diseases, including Parkinson disease (PD). Multiple homeostatic mechanisms exist to ensure mitochondrial integrity, including the selective autophagic program mitophagy, that is activated during starvation or in response to mitochondrial dysfunction. Following prolonged loss of potential across the inner mitochondrial membrane (ΔΨ), PTEN-induced putative kinase 1 (PINK1) and the E3-ubiquitin ligase PARK2 work in the same pathway to trigger mitophagy of dysfunctional mitochondria.

View Article and Find Full Text PDF

The Lkb1 tumor suppressor exerts its biological effects through phosphorylation and consequent activation of the AMP kinase (AMPK) family. Extensive genetic and biochemical evidence supports a role for Lkb1 in cell cycle arrest, establishment of cell polarity, and cellular energy metabolism. However, the role of Lkb1 and the AMPK family in beta cell function in vivo has not been established.

View Article and Find Full Text PDF

The transcription factor encoded by the murine ecotropic integration site 1 gene (MEIS1) is a partner of HOX and PBX proteins. It has been implicated in embryonic patterning and leukemia, and causally linked to restless legs syndrome. The MEIS1A C terminus harbors a transcriptional activation domain that is stimulated by protein kinase A (PKA) in a manner dependent on the co-activator of cAMP response element-binding protein (CREB), CREB-binding protein (CBP).

View Article and Find Full Text PDF

CREB is a cAMP- and calcium-responsive transcriptional activator that is required for islet beta cell proliferation and survival. Glucose and incretin hormones elicit beta cell insulin secretion and promote synergistic CREB activity by inducing the nuclear relocalization of TORC2 (also known as Crtc2), a coactivator for CREB. In islet cells under basal conditions when CREB activity is low, TORC2 is phosphorylated and sequestered in the cytoplasm by 14-3-3 proteins.

View Article and Find Full Text PDF