Understanding neurodevelopmental trajectories and behavioral profiles in SCN1A-related epilepsy syndromes.

Background: A pathogenic variant in SCN1A can result in a spectrum of phenotypes, including Dravet syndrome (DS) and genetic epilepsy with febrile seizures plus (GEFS + ) syndrome. Dravet syndrome (DS) is associated with refractory seizures, developmental delay, intellectual disability (ID), motor impairment, and challenging behavior(1,2). GEFS + is a less severe phenotype in which cognition is often normal and seizures are less severe.

Genotype-phenotype associations in 1018 individuals with SCN1A-related epilepsies.

Objective: SCN1A variants are associated with epilepsy syndromes ranging from mild genetic epilepsy with febrile seizures plus (GEFS+) to severe Dravet syndrome (DS). Many variants are de novo, making early phenotype prediction difficult, and genotype-phenotype associations remain poorly understood.

Methods: We assessed data from a retrospective cohort of 1018 individuals with SCN1A-related epilepsies.

Hope, but never expect? Comparing parents' pre- and post-disclosure attitudes toward return of results from diagnostic exome sequencing for their child.

Background: Counseling for whole-exome sequencing (WES) could benefit from aligning parents' pre- and post-disclosure attitudes. A few studies have qualitatively compared parents' pre- and post-disclosure attitudes toward receiving WES results for their child in a diagnostic setting. This study explored these attitudes in the context of children with a developmental delay.

The Association between Intracranial Calcifications and Symptoms in Patients with Primary Familial Brain Calcification.

(1) Background: Primary Familial Brain Calcification (PFBC) is a neurodegenerative disease characterized by bilateral calcifications of the basal ganglia and other intracranial areas. Many patients experience symptoms of motor dysfunction and cognitive disorders. The aim of this study was to investigate the association between the amount and location of intracranial calcifications with these symptoms.

The effects of etidronate on brain calcifications in Fahr's disease or syndrome: rationale and design of the randomised, placebo-controlled, double-blind CALCIFADE trial.

Background: Fahr's disease and syndrome are rare disorders leading to calcification of the small arteries in the basal ganglia of the brain, resulting in a wide range of symptoms comprising cognitive decline, movement disorders and neuropsychiatric symptoms. No disease-modifying therapies are available. Studies have shown the potential of treatment of ectopic vascular calcifications with bisphosphonates.

Clinical and electrophysiological features of SCN8A variants causing episodic or chronic ataxia.

Background: Variants in SCN8A are associated with a spectrum of epilepsies and neurodevelopmental disorders. Ataxia as a predominant symptom of SCN8A variation has not been well studied. We set out to investigate disease mechanisms and genotype-phenotype correlations of SCN8A-related ataxia.

Uncertain futures and unsolicited findings in pediatric genomic sequencing: guidelines for return of results in cases of developmental delay.

Background: Massively parallel sequencing techniques, such as whole exome sequencing (WES) and whole genome sequencing (WGS), may reveal unsolicited findings (UFs) unrelated to the diagnostic aim. Such techniques are frequently used for diagnostic purposes in pediatric cases of developmental delay (DD). Yet policy guidelines for informed consent and return of UFs are not well equipped to address specific moral challenges that may arise in these children's situations.

Identification of candidate genes for developmental colour agnosia in a single unique family.

Colour agnosia is a disorder that impairs colour knowledge (naming, recognition) despite intact colour perception. Previously, we have identified the first and only-known family with hereditary developmental colour agnosia. The aim of the current study was to explore genomic regions and candidate genes that potentially cause this trait in this family.

Epilepsy is an important feature of KBG syndrome associated with poorer developmental outcome.

Objective: The aim of this study was to describe the epilepsy phenotype in a large international cohort of patients with KBG syndrome and to study a possible genotype-phenotype correlation.

Methods: We collected data on patients with ANKRD11 variants by contacting University Medical Centers in the Netherlands, an international network of collaborating clinicians, and study groups who previously published about KBG syndrome. All patients with a likely pathogenic or pathogenic ANKRD11 variant were included in our patient cohort and categorized into an "epilepsy group" or "non-epilepsy group".

Challenging behavior in children and adolescents with Dravet syndrome: Exploring the lived experiences of parents.

Background: Dravet syndrome (DS) is a monogenic syndrome associated with SCN1A mutations in the majority of patients and characterized by devastating epilepsy, that may be life-threatening. Aside from refractory seizures, core symptoms of DS include behavioral difficulties, developmental delay, cognitive impairment, and motor dysfunction. Previous DS research has mainly focused on epileptic seizures and pharmacological management and less on behavioral difficulties.

KCNQ2 R144 variants cause neurodevelopmental disability with language impairment and autistic features without neonatal seizures through a gain-of-function mechanism.

Background: Prior studies have revealed remarkable phenotypic heterogeneity in KCNQ2-related disorders, correlated with effects on biophysical features of heterologously expressed channels. Here, we assessed phenotypes and functional properties associated with KCNQ2 missense variants R144W, R144Q, and R144G. We also explored in vitro blockade of channels carrying R144Q mutant subunits by amitriptyline.

Distal spinal muscular atrophy featured by predominant calf muscle involvement in VRK1 associated disease - Case series and review.

We describe the shared clinical, biochemical, radiological and myopathological characteristics of four patients with distal spinal muscular atrophy (dSMA) caused by vaccinia-related kinase 1 (VRK1) variants and provide a review of the literature on phenotype-genotype correlations in VRK1-related disease. The clinical phenotype was characterized by adult-onset dSMA with predominant calf muscle involvement and mildly elevated serum creatinine kinase (CK) levels. Muscle imaging showed predominant atrophy and fatty replacement of calf muscles.

HEATR3 variants impair nuclear import of uL18 (RPL5) and drive Diamond-Blackfan anemia.

The congenital bone marrow failure syndrome Diamond-Blackfan anemia (DBA) is typically associated with variants in ribosomal protein (RP) genes impairing erythroid cell development. Here we report multiple individuals with biallelic HEATR3 variants exhibiting bone marrow failure, short stature, facial and acromelic dysmorphic features, and intellectual disability. These variants destabilize a protein whose yeast homolog is known to synchronize the nuclear import of RPs uL5 (RPL11) and uL18 (RPL5), which are both critical for producing ribosomal subunits and for stabilizing the p53 tumor suppressor when ribosome biogenesis is compromised.

coding variants in the gene cause a neurodevelopmental disorder with intellectual disability.

Background: High-impact pathogenic variants in more than a thousand genes are involved in Mendelian forms of neurodevelopmental disorders (NDD).

Methods: This study describes the molecular and clinical characterisation of 28 probands with NDD harbouring heterozygous coding variants, occurring de novo for all those whose transmission could have been verified (26/28).

Results: A total of 15 unique variants leading to amino acid changes or deletions were identified: 12 missense variants, two in-frame deletions of one codon, and one canonical splice variant leading to a deletion of two amino acid residues.

Related Developmental and Epileptic Encephalopathy: Phenotypic and Genotypic Spectrum.

Background And Objectives: Purine-rich element-binding protein A () gene encodes Pur-α, a conserved protein essential for normal postnatal brain development. Recently, a syndrome characterized by intellectual disability, hypotonia, epilepsy, and dysmorphic features was suggested. The aim of this study was to define and expand the phenotypic spectrum of syndrome by collecting data, including EEG, from a large cohort of affected patients.

Genotype-phenotype correlations in SCN8A-related disorders reveal prognostic and therapeutic implications.

We report detailed functional analyses and genotype-phenotype correlations in 392 individuals carrying disease-causing variants in SCN8A, encoding the voltage-gated Na+ channel Nav1.6, with the aim of describing clinical phenotypes related to functional effects. Six different clinical subgroups were identified: Group 1, benign familial infantile epilepsy (n = 15, normal cognition, treatable seizures); Group 2, intermediate epilepsy (n = 33, mild intellectual disability, partially pharmaco-responsive); Group 3, developmental and epileptic encephalopathy (n = 177, severe intellectual disability, majority pharmaco-resistant); Group 4, generalized epilepsy (n = 20, mild to moderate intellectual disability, frequently with absence seizures); Group 5, unclassifiable epilepsy (n = 127); and Group 6, neurodevelopmental disorder without epilepsy (n = 20, mild to moderate intellectual disability).

Pathogenic MAST3 Variants in the STK Domain Are Associated with Epilepsy.

Objective: The MAST family of microtubule-associated serine-threonine kinases (STKs) have distinct expression patterns in the developing and mature human and mouse brain. To date, only MAST1 has been conclusively associated with neurological disease, with de novo variants in individuals with a neurodevelopmental disorder, including a mega corpus callosum.

Methods: Using exome sequencing, we identify MAST3 missense variants in individuals with epilepsy.