Loss of ANK3 Function Causes a Recessive Neurodevelopmental Disorder with Cerebellar Ataxia.

Background: ANK3 encodes ankyrin-G, a key scaffolding protein essential for neuronal function. While both monoallelic and biallelic ANK3 variants have been linked to neurodevelopmental disorders (NDDs), existing evidence for their pathogenicity and clinical correlation remains limited and heterogeneous.

Objective: To delineate the clinical features associated with biallelic ANK3 predicted loss-of-function (pLOF) variants.

Most prominent challenges in translational neuroscience and strategic solutions to bridge the gaps: Perspectives from an editorial board interrogation.

Recent progress in translational neuroscience has significantly advanced our understanding of neurological diseases. Research progress closely went in line with innovations in research methods, which have expanded our insights considerably beyond previous limits. However, despite the development of disease-modifying treatments, therapeutic options in brain diseases still lag behind fundamental discoveries in basic neuroscience.

Ritscher-Schinzel syndrome can be characterized as an endosomal recyclinopathy.

Ritscher-Schinzel syndrome (RSS) is a congenital malformation syndrome characterized by cerebellar, cardiac, and craniofacial malformations and phenotypes associated with liver, skeletal, and kidney dysfunction. The genetic cause of RSS remains to be fully defined, and limited information is available regarding the root cause of the multiple tissue phenotypes. Causative mutations in the Commander multiprotein assembly are an emerging feature of this syndrome.

ADAT3-related neurodevelopmental disorder in 24 new patients with a high frequency of the p.Val144Met and a new founder variant.

Biallelic variants in the adenosine deaminase tRNA specific 3 (ADAT3) gene are associated with a distinct neurodevelopmental disorder characterized by dysmorphic facies, poor growth, cognitive impairment, and variable brain anomalies. We describe 24 patients from 16 unrelated Egyptian families with ADAT3-related neurodevelopmental disorder. All patients presented with developmental delay, growth retardation, cognitive impairment, and the characteristic facial features of the disorder, which appears to be more recognizable in older patients.

The landscape of pediatric genetic white matter disorders at a tertiary referral hospital in Upper Egypt and the report of 31 novel variants.

Background: Leukodystrophies (LDs) and genetic leukoencephalopathies (GLEs) encompass the spectrum of genetic white matter disorders (GWMDs). Despite their clinical significance, limited studies have investigated GWMDs in Egypt. Therefore, this study aimed to characterize pediatric patients diagnosed with GWMDs in the Beni-Suef Governorate, Upper Egypt.

Pathogenic variants in Cause a Spectrum of Neurodevelopmental and Neurodegenerative Disorders with Lysosomal Dysfunction.

encodes a subunit of the BLOC-one-related complex (BORC), which is known to mediate the kinesin-dependent anterograde movement of lysosomes. Using whole-exome sequencing, we identified 12 cases from seven families carrying bi-allelic variants, including four loss-of-function and two missense variants. Carriers of homozygous loss-of-function variants presented with prenatally lethal arthrogryposis multiplex congenita, brain malformations, and neuropathological evidence of diffuse neuroaxonal dystrophy.

Inherited deficiency of DIAPH1 identifies a DNA double strand break repair pathway regulated by γ-actin.

DNA double strand break repair (DSBR) represents a fundamental process required to maintain genome stability and prevent the onset of disease. Whilst cell cycle phase and the chromatin context largely dictate which repair pathway is utilised to restore damaged DNA, it has been recently shown that nuclear actin filaments play a major role in clustering DNA breaks to facilitate DSBR by homologous recombination (HR). However, the mechanism with which nuclear actin and the different actin nucleating factors regulate HR is unclear.

HPDL Variant Type Correlates With Clinical Disease Onset and Severity.

Objective: Recently, a mitochondrial encephalopathy due to biallelic HPDL variants was described, associated with a broad range of clinical manifestations ranging from severe, infantile-onset neurodegeneration to adolescence-onset hereditary spastic paraplegia. HPDL converts 4-hydroxyphenylpyruvate acid (4-HPPA) into 4-hydroxymandelate (4-HMA), necessary for the synthesis of the mitochondrial electron transporter CoQ10. This suggests a possible bypass of the metabolic block by 4-HMA treatment; however, genotype-phenotype correlations are lacking.

Consensus of Expert Opinion for the Diagnosis and Management of Hypermanganesaemia With Dystonia 1 and 2.

Hypermanganesaemia with Dystonia 1 and 2 (HMNDYT1 and 2) are inherited, autosomal recessive disorders caused by pathogenic variants in the genes encoding the manganese transporters SLC30A10 and SLC39A14, respectively. Impaired hepatic and enterocytic manganese uptake (SLC39A14) and excretion (SLC30A10) lead to deposition of manganese in the basal ganglia resulting in childhood-onset dystonia-parkinsonism. HMNDYT1 is characterized by additional features due to manganese accumulation in the liver causing cirrhosis, polycythaemia, and depleted iron stores.

Analysis of Copy Number Variants Is an Important Consideration in Exome Sequencing.

Copy number variants (CNVs) contribute significantly to the pathogenicity of rare genetic diseases and tend to have a more severe effect on phenotype compared to single nucleotide variants (SNVs). In the past decades, exome sequencing (ES) has proven valuable input in the characterization of underlying genetic defects. Our aim was to investigate the impact of integrating CNV analysis tools into standard ES analysis on its diagnostic yield.

Bi-allelic UGGT1 variants cause a congenital disorder of glycosylation.

Congenital disorders of glycosylation (CDGs) comprise a large heterogeneous group of metabolic conditions caused by defects in glycoprotein and glycolipid glycan assembly and remodeling, a fundamental molecular process with wide-ranging biological roles. Herein, we describe bi-allelic UGGT1 variants in fifteen individuals from ten unrelated families of various ethnic backgrounds as a cause of a distinctive CDG of variable severity. The cardinal clinical features of UGGT1-CDG involve developmental delay, intellectual disability, seizures, characteristic facial features, and microcephaly in the majority (9/11 affected individuals for whom measurements were available).

Bi-allelic pathogenic variants in TRMT1 disrupt tRNA modification and induce a neurodevelopmental disorder.

The post-transcriptional modification of tRNAs plays a crucial role in tRNA structure and function. Pathogenic variants in tRNA-modification enzymes have been implicated in a wide range of human neurodevelopmental and neurological disorders. However, the molecular basis for many of these disorders remains unknown.

Mitochondrial DNA variant detection in over 6,500 rare disease families by the systematic analysis of exome and genome sequencing data resolves undiagnosed cases.

Variants in the mitochondrial genome (mtDNA) cause a diverse collection of mitochondrial diseases and have extensive phenotypic overlap with Mendelian diseases encoded on the nuclear genome. The mtDNA is not always specifically evaluated in patients with suspected Mendelian disease, resulting in overlooked diagnostic variants. Here, we analyzed a cohort of 6,660 rare disease families (5,625 genetically undiagnosed [84%]) from the Genomics Research to Elucidate the Genetics of Rare diseases (GREGoR) Consortium, as well as other rare disease cohorts.

Novel biallelic COL25A1 variants broaden the clinical spectrum from congenital cranial dysinnervation disorders to fetal lethal phenotypes.

Biallelic variants in COL25A1 have been associated with isolated congenital cranial dysinnervation disorders (CCDDs) and arthrogryposis multiplex congenital (AMC) with or without CCDD. COL25A1 encodes collagen XXV that belongs to the subfamily of membrane-associated collagens with interrupted triple helices. COL25A1 contains four non-collagenous and three collagenous domains.

The contribution of de novo coding mutations to meningomyelocele.

Meningomyelocele (also known as spina bifida) is considered to be a genetically complex disease resulting from a failure of the neural tube to close. Individuals with meningomyelocele display neuromotor disability and frequent hydrocephalus, requiring ventricular shunting. A few genes have been proposed to contribute to disease susceptibility, but beyond that it remains unexplained.

Biallelic variants in encoding a subunit of the TFIIIC2 complex are associated with neurodevelopmental phenotypes in humans and zebrafish.

RNA polymerase III transcribes essential non-coding RNAs, a process regulated by transcription factors TFIIIB and TFIIIC. Although germline variants in TFIIIC subunit genes have been described in a few patients with neurodevelopmental disorders, the associated pathogenesis and clinical spectrum are not yet well defined. Herein, we describe the identification of biallelic variants in which encodes a key component of the TFIIIC subunit, in four patients from three unrelated families of different ethnicities collected through GeneMatcher.

Delineating the Clinical and Brain Imaging Characteristics of the Neonatal Form of CSTB -Related Neurodevelopmental Disorders.

Cystatin B gene (CSTB) is responsible for the most common childhood onset type of progressive myoclonic epilepsy (EPM1A). More recently, biallelic CSTB variants were described in four patients with a neonatal onset phenotype of microcephaly, diffuse hypomyelination, brain atrophic changes, and dyskinesia. Herein, we describe the clinical and molecular characterization of five additional patients in whom exome sequencing detected a splice variant (c.

RNA methyltransferase SPOUT1/CENP-32 links mitotic spindle organization with the neurodevelopmental disorder SpADMiSS.

SPOUT1/CENP-32 encodes a putative SPOUT RNA methyltransferase previously identified as a mitotic chromosome associated protein. SPOUT1/CENP-32 depletion leads to centrosome detachment from the spindle poles and chromosome misalignment. Aided by gene matching platforms, here we identify 28 individuals with neurodevelopmental delays from 21 families with bi-allelic variants in SPOUT1/CENP-32 detected by exome/genome sequencing.

A Unique Derivative Chromosome 4 with a Predominant 4p16.3 Microduplication Phenotype and a Literature Review.

Introduction: Constitutional structural abnormalities affecting chromosome 4 result in variable distinct phenotypic traits including duplication 4p syndrome, deletion 4p or Wolf-Hirschhorn syndrome (WHS), deletion 4q and duplication 4q syndromes. Complex rearrangements involving both chromosome 4 arms are very rarely reported with different break points occurring within regions of 4p13-p16 and 4q32-35. They most commonly occur in familial cases due to parental pericentric inversion resulting in a recombinant chromosome 4 "rec(4).

Genomics of rare diseases in the Greater Middle East.

The Greater Middle East (GME) represents a concentrated region of unparalleled genetic diversity, characterized by an abundance of distinct alleles, founder mutations and extensive autozygosity driven by high consanguinity rates. These genetic hallmarks present a unique, yet vastly untapped resource for genomic research on Mendelian diseases. Despite this immense potential, the GME continues to face substantial challenges in comprehensive data collection and analysis.

Integrating Prenatal Exome Sequencing and Ultrasonographic Fetal Phenotyping for Assessment of Congenital Malformations: High Molecular Diagnostic Yield and Novel Phenotypic Expansions in a Consanguineous Cohort.

To evaluate the diagnostic yield of prenatal exome sequencing (pES) in fetuses with structural anomalies detected by prenatal ultrasound in a consanguineous population. This was a prospective study of 244 anomalous fetuses from unrelated consanguineous Egyptian families. Detailed phenotyping was performed throughout pregnancy and postnatally, and pES data analysis was conducted.

Lethal Phenotype and Expansion of the Clinical Spectrum of Biallelic Loss of Function Variant in SENP7 Gene Unveiled by Whole Exome Sequencing.

SUMOylation involves covalent attachment of small ubiquitin-like modifier (SUMO) proteins to specific lysine residues on target proteins and regulates various aspects of their function. Sentrin-specific proteases (SENPs) are key players in both the conjugation reaction of SUMO proteins to their targets and the subsequent deconjugation of SUMO-conjugated substrates. Here, we provide the first comprehensive prenatal description of a lethal syndrome linked to a novel homozygous stop-gain variant in SENP7 c.

Lipidomic profiling of mouse brain and human neuron cultures reveals a role for in mTOR-dependent neuronal migration.

Mutations in lipid regulator genes are a frequent cause of autism spectrum disorder, including those regulating phosphatidylinositol (PI) and phosphoinositide 3-kinase signaling. encodes a key acyltransferase in PI synthesis and is mutated in an autism-related condition with neurodevelopmental delay and epilepsy. Using liquid chromatography-tandem mass spectrometry, we analyzed the PI-associated glycerolipidome in mice and humans during neurodevelopment and found dynamic regulation at times corresponding to neural apoptosis in the brains of knockout mice.

Clinical and genetic characterization of a progressive RBL2-associated neurodevelopmental disorder.

Retinoblastoma (RB) proteins are highly conserved transcriptional regulators that play important roles during development by regulating cell-cycle gene expression. RBL2 dysfunction has been linked to a severe neurodevelopmental disorder. However, to date, clinical features have been described in only six individuals carrying five biallelic predicted loss-of-function (pLOF) variants.