Updates on neurologic manifestations of mitochondrial disease.

Purpose Of Review: Primary mitochondrial disease (PMD) is diverse both genetically and phenotypically. Neurologic manifestations are present at a high rate and often pose complications for providers. The review will discuss common manifestations and how advances in genetic testing have broadened understanding of PMDs.

Novel pathogenic variant in a mild case of type B molybdenum cofactor deficiency: case report and literature review.

Background: Molybdenum cofactor deficiency (MoCD) is a rare metabolic disorder caused by pathogenic variants in the highly conserved biosynthetic pathway of molybdenum cofactor (MoCo), resulting in sulfite intoxication. MoCD may present in a clinically severe, fatal form marked by intractable seizures after birth, hyperekplexia, microcephaly and cerebral atrophy, or a later onset form with a more varied clinical course. Three types of MoCD have been described based on the effected gene along the MoCo synthesis pathway: type A (MOCS1); type B (MOCS2 or MOCS3) and type C (GPHN).

Factors Associated with Pathway-Concordant Neuroimaging for Pediatric Ischemic Stroke.

Objective: To determine factors associated with magnetic resonance imaging (MRI) and noninvasive diagnostic angiography among children presenting to the emergency department (ED) with acute ischemic stroke.

Study Design: We performed a cross-sectional study using data from >50 US children's hospitals. We included children 29 days through 17 years old hospitalized from the ED with an International Classification of Diseases, Tenth Revision, Clinical Modification, diagnosis code for acute ischemic stroke between October 1, 2015, and November 30, 2022.

Axonal polyneuropathy and ataxia in children: consider Perrault Syndrome, a case report.

Background: Perrault Syndrome (PRLTS) is a rare, autosomal recessive disorder that presents with bilateral sensorineural hearing loss in all patients and gonadal dysfunction in females. It has been linked to variants in CLPP, ERAL1, HARS2, HSD17B4, LARS2, and TWNK genes. All reported cases due to TWNK variants have included neurologic features, such as ataxia and axonal sensorimotor neuropathy.

DEPDC5-dependent mTORC1 signaling mechanisms are critical for the anti-seizure effects of acute fasting.

Caloric restriction and acute fasting are known to reduce seizures but through unclear mechanisms. mTOR signaling has been suggested as a potential mechanism for seizure protection from fasting. We demonstrate that brain mTORC1 signaling is reduced after acute fasting of mice and that neuronal mTORC1 integrates GATOR1 complex-mediated amino acid and tuberous sclerosis complex (TSC)-mediated growth factor signaling.

mTORC1 functional assay reveals SZT2 loss-of-function variants and a founder in-frame deletion.

Biallelic pathogenic variants in SZT2 result in a neurodevelopmental disorder with shared features, including early-onset epilepsy, developmental delay, macrocephaly, and corpus callosum abnormalities. SZT2 is as a critical scaffolding protein in the amino acid sensing arm of the mTORC1 signalling pathway. Due to its large size (3432 amino acids), lack of crystal structure, and absence of functional domains, it is difficult to determine the pathogenicity of SZT2 missense and in-frame deletions, but these variants are increasingly detected and reported by clinical genetic testing in individuals with epilepsy.

The Gro3p factor: Restoring NAD+/NADH homeostasis to ameliorate mitochondrial disease.

Leigh syndrome, a mitochondrial disease, can be modeled in mice with a deficiency in mitochondrial complex I that results in a decreased NAD+/NADH ratio. In this issue of Cell Metabolism, Liu et al. (2021) identify glycerol-3-phosphate (Gro3P) biosynthesis as a method for regenerating cytosolic NAD+ to ameliorate pathology in this mitochondrial disease model.

MRI of 3-hydroxyisobutyryl-CoA hydrolase (HIBCH) deficiency.

3-Hydroxyisobutyryl-CoA hydrolase (HIBCH) deficiency is a rare mitochondrial disorder of valine metabolism which may present with motor delay, hypotonia, ataxia, dystonia, seizures poor feeding, and organic aciduria. Neuroimaging findings include signal abnormalities of the deep gray matter, particularly the globus pallidi, and cerebral peduncles. We report a 15-month-old male patient with HIBCH deficiency who presented with paroxysmal tonic upgaze of infancy, motor delay, and hypotonia.

Mitochondrial Dysfunction in Fragile-X Syndrome: Plugging the Leak May Save the Ship.

Recent work by Licznerski et al. suggests that mutant FMRP linked to Fragile-X syndrome elevates the inner mitochondrial membrane proton leak, leading to increased metabolism and changes in protein synthesis that trigger impaired synaptic maturation and autistic behaviors.

NAD+ Regeneration Rescues Lifespan, but Not Ataxia, in a Mouse Model of Brain Mitochondrial Complex I Dysfunction.

Mitochondrial complex I regenerates NAD+ and proton pumps for TCA cycle function and ATP production, respectively. Mitochondrial complex I dysfunction has been implicated in many brain pathologies including Leigh syndrome and Parkinson's disease. We sought to determine whether NAD+ regeneration or proton pumping, i.

Dexamethasone after early-life seizures attenuates increased susceptibility to seizures, seizure-induced microglia activation and neuronal injury later in life.

Chronic epilepsy can begin with isolated early-life prolonged seizures followed by remission and the re-emergence of seizures later in life. Seizures are known to trigger a neuroinflammatory response to promote neuronal damage and increase the risk of epilepsy. We examined whether post-seizure anti-inflammatory treatment with dexamethasone after early-life seizures could decrease future seizure susceptibility and ameliorate heightened microglia activation and cell injury in response to later-life seizures.

Fenfluramine: New Treatment for Seizures in Dravet Syndrome.

Investigators for the FAiRE DS Study Group assessed the efficacy and safety of Fenfluramine for treating seizures in patients less than 18 y.o. with Dravet Syndrome in an international double-blind, placebo-controlled clinical trial.

A Promising Small Molecule for Vanishing White Matter Disease.

Investigators from Calico Life Sciences LLC and AbbVie report the effects of a novel drug targeting the genetic basis of Vanishing White Matter Disease (VWMD).

Anticonvulsant Medications in Mitochondrial Disease.

Researchers from Vienna, Austria and Sao Paulo, Brazil studied the known effects of anticonvulsant drugs on mitochondria, using a literature search to include only references to epilepsy associated with mitochondrial disease, and a specific anti-convulsant drug (i.e. levetiracetam) with a specific mitochondrial function (i.

Use of gadolinium-based magnetic resonance imaging contrast agents and awareness of brain gadolinium deposition among pediatric providers in North America.

Background: Numerous recent articles have reported brain gadolinium deposition when using linear but not macrocyclic gadolinium-based contrast agents (GBCAs).

Objective: To determine the current landscape of gadolinium use among pediatric institutions and the knowledge base of radiologists and referring providers with regard to GBCAs and brain gadolinium deposition.

Materials And Methods: We e-mailed voluntary closed surveys to 5,390 physicians in various pediatric professional societies between January 2016 and March 2016.

Diffusion Tensor Imaging of Epileptogenic Lesions in TSC.

Investigators from University of California Los Angeles, studied whether epileptogenic tubers in Tuberous Sclerosis Complex (TSC) can be identified by diffusion tensor imaging (DTI).

Localized CCR2 Activation in the Bone Marrow Niche Mobilizes Monocytes by Desensitizing CXCR4.

Inflammatory (classical) monocytes residing in the bone marrow must enter the bloodstream in order to combat microbe infection. These monocytes express high levels of CCR2, a chemokine receptor whose activation is required for them to exit the bone marrow. How CCR2 is locally activated in the bone marrow and how their activation promotes monocyte egress is not understood.

Foxc1 dependent mesenchymal signalling drives embryonic cerebellar growth.

Loss of Foxc1 is associated with Dandy-Walker malformation, the most common human cerebellar malformation characterized by cerebellar hypoplasia and an enlarged posterior fossa and fourth ventricle. Although expressed in the mouse posterior fossa mesenchyme, loss of Foxc1 non-autonomously induces a rapid and devastating decrease in embryonic cerebellar ventricular zone radial glial proliferation and concurrent increase in cerebellar neuronal differentiation. Subsequent migration of cerebellar neurons is disrupted, associated with disordered radial glial morphology.

Impact of fiducial arrangement and registration sequence on target accuracy using a phantom frameless stereotactic navigation model.

Modern frameless stereotactic techniques utilize scalp fiducial markers for registration. Anecdotal reports from surgeons indicate a variety of methods for improving accuracy using different fiducial arrangements and registration sequences. The few published studies on registration accuracy do not provide a simple and systematic method for determining target accuracy.

CXCR4 signaling regulates radial glial morphology and cell fate during embryonic spinal cord development.

Embryonic meninges secrete the chemokine SDF-1/CXCL12 as a chemotactic guide for migrating neural stem cells, but SDF-1 is not known to directly regulate the functions of radial glia. Recently, the developing meninges have been shown to regulate radial glial function, yet the mechanisms and signals responsible for this phenomenon remain unclear. Moreover, as a nonmigratory cell type, radial glia do not conform to traditional models associated with chemokine signaling in the central nervous system.

Emergent intrathecal baclofen withdrawal after pseudomeningocele aspiration.

Intrathecal baclofen (ITB) infusion has become a common treatment for severe spasticity. Many complications of these drug delivery systems have been reported such as those related to improper dosing, mechanical failure of the implanted pump or catheter, or post-operative wound issues. We report a case of ITB withdrawal after pseudomeningocele aspiration.

CXCL12 signaling in the development of the nervous system.

Chemokines are small, secreted proteins that have been shown to be important regulators of leukocyte trafficking and inflammation. All the known effects of chemokines are transduced by action at a family of G protein coupled receptors. Two of these receptors, CCR5 and CXCR4, are also known to be the major cellular receptors for HIV-1.