Successful Lisdexamfetamine Treatment for Behavioral Arrests, Paroxysmal Nonkinesiogenic Dyskinesia, and Attention Deficits Due to a Previously Unreported KCNMA1 Variant.

Disease-causing variants in are associated with a spectrum of epilepsy and/or movement disorders, often with additional developmental issues or intellectual impairment. Monoallelic gain-of-function variants often lead to paroxysmal nonkinesigenic dyskinesia (PNKD). While the treatment mechanism is unknown, dextroamphetamine and its prodrug lisdexamfetamine have been shown to successfully control the debilitating PNKD with up to several hundred daily incidents in one patient with the (NM_001161352.

Hearing rehabilitation in SERAC1 related MEGD(H)EL syndrome - implications from a multi-center retrospective cohort study.

Objective: 3-methylglutaconic aciduria (MEG), dystonia-deafness (D), (hepatopathy (H)), encephalopathy (E), and Leigh-like-syndrome (L) (MEGD(H)EL) syndrome is a rare, severely disabling progressive mitochondrial disease associated with biallelic pathogenic variants in SERAC1. Knowledge about hearing loss (HL) and hearing rehabilitation is scarce but highly sought after for best possible care in the absence of causative treatment.

Methods: Retrospective cross-sectional study.

Deciphering DST-associated disorders: biallelic variants affecting DST-b cause a congenital myopathy.

Dystonin (DST) encodes three major isoforms, DST-a, DST-b, and DST-e. Biallelic pathogenic variants in DST have previously been associated with two allelic monogenic disorders: Hereditary Sensory and Autonomic Neuropathy type VI (caused by a loss of DST-a) and Epidermolysis bullosa simplex 3 (caused by a loss of DST-e). We investigated patients diagnosed with congenital myopathy using exome or genome sequencing.

Biallelic NSUN3 Variants Cause Diverse Phenotypic Spectrum Disease: From Isolated Optic Atrophy to Severe Early-Onset Mitochondrial Disorder.

Purpose: Primary mitochondrial disorders (PMDs) are a clinically heterogeneous group of genetic disorders that can affect many tissues, with a broad phenotypic spectrum ranging from isolated organ involvement to severe early-onset multisystem disease. Visual loss from optic atrophy is a frequent clinical manifestation of mitochondrial cytopathies. This study aimed to identify the missing heritability in previously unsolved cases of suspected isolated or syndromic optic neuropathy.

Hepatic Form of Dihydrolipoamide Dehydrogenase Deficiency (DLDD): Phenotypic Spectrum, Laboratory Findings, and Therapeutic Approaches in 52 Patients.

Dihydrolipoamide dehydrogenase deficiency (MIM 246900/DLDD) is an autosomal recessive mitochondrial disease with three clinical subgroups. The hepatic form leads to recurrent metabolic decompensations often accompanied by elevated levels of liver transaminases (ELT) in blood, sometimes progressing to acute liver failure (ALF). Genetically, it is linked to the p.

Dominant variants in major spliceosome U4 and U5 small nuclear RNA genes cause neurodevelopmental disorders through splicing disruption.

The major spliceosome contains five small nuclear RNAs (snRNAs; U1, U2, U4, U5 and U6) essential for splicing. Variants in RNU4-2, encoding U4, cause a neurodevelopmental disorder called ReNU syndrome. We investigated de novo variants in 50 snRNA-encoding genes in a French cohort of 23,649 individuals with rare disorders and gathered additional cases through international collaborations.

Mitochondrial Oxidative Phosphorylation Alterations in Placental Tissues from Early- and Late-Onset Preeclampsia.

Preeclampsia (PE), a pregnancy complication characterized by high blood pressure and organ damage, has been suggested to be associated with mitochondrial dysfunction, although evidence remains limited. This study aimed to investigate the activity of oxidative phosphorylation (OXPHOS) enzymes and the expression of related proteins in placental tissues from women diagnosed with early-onset preeclampsia (eoPE, <34 weeks of gestation), late-onset preeclampsia (loPE, ≥34 weeks of gestation), and normotensive controls. Placental samples were analyzed using immunohistochemistry, western blotting, and enzymatic activity assays to assess the activity and expression of OXPHOS complexes.

Bi-allelic MED16 variants cause a MEDopathy with intellectual disability, motor delay, and craniofacial, cardiac, and limb malformations.

The Mediator complex regulates protein-coding gene transcription by coordinating the interaction of upstream enhancers with the basal transcription machinery at the promoter. Pathogenic variants in Mediator subunits typically lead to neurodevelopmental or neurodegenerative disorders with variable clinical presentations, designated as MEDopathies. Here, we report the identification of 25 individuals from 18 families with bi-allelic MED16 variants who have a multiple congenital anomalies (MCAs)-intellectual disability syndrome.

Mitochondrial disorder diagnosis and management- what the pediatric neurologist wants to know.

Childhood-onset mitochondrial disorders are rare genetic diseases that often manifest with neurological impairment due to altered mitochondrial structure or function. To date, pathogenic variants in 373 genes across the nuclear and mitochondrial genomes have been linked to mitochondrial disease, but the ensuing genetic and clinical complexity of these disorders poses considerable challenges to their diagnosis and management. Nevertheless, despite the current lack of curative treatment, recent advances in next generation sequencing and -omics technologies have laid the foundation for precision mitochondrial medicine through enhanced diagnostic accuracy and greater insight into pathomechanisms.

Missense variants in the TRPM7 α-kinase domain are associated with recurrent pediatric acute liver failure.

Background: Pediatric acute liver failure (PALF) is a rare and life-threatening condition. In up to 50% of PALF cases, the underlying etiology remains unknown during routine clinical testing. This lack of knowledge complicates clinical management and liver transplantation decisions.

The phenotypic spectrum of deficiency.

The gene product (protein PTCD3 or MRPS39) forms the entry channel of the mitochondrial small ribosomal subunit and binds to single-stranded mRNA. Here, we expand on the clinical manifestations of pathogenic variants by describing an early-onset patient with Leigh-like syndrome and two patients with milder form of disease, with combined oxidative phosphorylation deficiency. A 34-year-old male and his 33-year-old sister both have horizontal nystagmus, pronounced rough tremor, truncal ataxia, dysmetria, spasticity and hyperreflexia.

Dihydrolipoamide dehydrogenase deficiency in five siblings with variable phenotypes, including fulminant fatal liver failure despite good engraftment of transplanted liver.

Dihydrolipoamide dehydrogenase (DLD) deficiency can, in one of its forms, be a rare cause of acute liver failure. Clinical presentation is nonspecific. Biochemical findings can reflect metabolic block, but vary depending on patient and his condition.

Anaplerotic Therapy Using Triheptanoin in Two Brothers Suffering from Aconitase 2 Deficiency.

Citric acid cycle deficiencies are extremely rare due to their central role in energy metabolism. The gene encodes the mitochondrial isoform of aconitase (aconitase 2), the second enzyme of the citric acid cycle. Approximately 100 patients with aconitase 2 deficiency have been reported with a variety of symptoms, including intellectual disability, hypotonia, optic nerve atrophy, cortical atrophy, cerebellar atrophy, and seizures.

Clinical, Neuroimaging, and Metabolic Footprint of the Neurodevelopmental Disorder Caused by Monoallelic Variants.

Background And Objectives: Hexokinase 1 (encoded by ) catalyzes the first step of glycolysis, the adenosine triphosphate-dependent phosphorylation of glucose to glucose-6-phosphate. Monoallelic variants causing a neurodevelopmental disorder (NDD) have been reported in 12 individuals.

Methods: We investigated clinical phenotypes, brain MRIs, and the CSF of 15 previously unpublished individuals with monoallelic variants and an NDD phenotype.

Complex I, V, and MDH2 deficient human skin fibroblasts reveal distinct metabolic signatures by H HR-MAS NMR.

In this study, we investigated the metabolic signatures of different mitochondrial defects (two different complex I and complex V, and the one MDH2 defect) in human skin fibroblasts (HSF). We hypothesized that using a selective culture medium would cause defect specific adaptation of the metabolome and further our understanding of the biochemical implications for the studied defects. All cells were cultivated under galactose stress condition and compared to glucose-based cell culture condition.

Biallelic Cys141Tyr variant of SEL1L is associated with neurodevelopmental disorders, agammaglobulinemia, and premature death.

Suppressor of lin-12-like-HMG-CoA reductase degradation 1 (SEL1L-HRD1) ER-associated degradation (ERAD) plays a critical role in many physiological processes in mice, including immunity, water homeostasis, and energy metabolism; however, its relevance and importance in humans remain unclear, as no disease variant has been identified. Here, we report a biallelic SEL1L variant (p. Cys141Tyr) in 5 patients from a consanguineous Slovakian family.

De novo variants in RNF213 are associated with a clinical spectrum ranging from Leigh syndrome to early-onset stroke.

Purpose: RNF213, encoding a giant E3 ubiquitin ligase, has been recognized for its role as a key susceptibility gene for moyamoya disease. Case reports have also implicated specific variants in RNF213 with an early-onset form of moyamoya disease with full penetrance. We aimed to expand the phenotypic spectrum of monogenic RNF213-related disease and to evaluate genotype-phenotype correlations.

Investigating the role of ASCC1 in the causation of bone fragility.

Bi-allelic variants in cause the ultrarare bone fragility disorder "spinal muscular atrophy with congenital bone fractures-2" (SMABF2). However, the mechanism by which ASCC1 dysfunction leads to this musculoskeletal condition and the nature of the associated bone defect are poorly understood. By exome sequencing, we identified a novel homozygous deletion in in a female infant.