The characterization of new de novo CACNA1G variants affecting the intracellular gate of Cav3.1 channel broadens the spectrum of neurodevelopmental phenotypes in SCA42ND.

Purpose: Missense de novo variants in CACNA1G, which encodes the Cav3.1 T-type calcium channel, have been associated with a severe, early-onset form of cerebellar disorder with neurodevelopmental deficits (SCA42ND). We explored a large series of pediatric cases carrying heterozygous variants in CACNA1G to further characterize genotype-phenotype correlations in SCA42ND.

Biallelic EPB41L3 variants underlie a developmental disorder with seizures and myelination defects.

Erythrocyte membrane protein band 4.1 like 3 (EPB41L3: NM_012307.5), also known as DAL1, encodes the ubiquitously expressed, neuronally enriched 4.

Prenatal diagnosis of pontocerebellar hypoplasia with postnatal follow-up.

Objective: To describe the MR features enabling prenatal diagnosis of pontocerebellar hypoplasia (PCH).

Method: This was a retrospective single monocentre study. The inclusion criteria were decreased cerebellar biometry on dedicated neurosonography and available fetal Magnetic Resonance Imaging (MRI) with PCH diagnosis later confirmed either genetically or clinically on post-natal MRI or by autopsy.

: Next-generation sequencing sheds light on Witkop's classification.

Amelogenesis imperfecta (AI) is a heterogeneous group of genetic rare diseases disrupting enamel development (Smith et al., Front Physiol, 2017a, 8, 333). The clinical enamel phenotypes can be described as hypoplastic, hypomineralized or hypomature and serve as a basis, together with the mode of inheritance, to Witkop's classification (Witkop, J Oral Pathol, 1988, 17, 547-553).

Deficiency of the minor spliceosome component U4atac snRNA secondarily results in ciliary defects in human and zebrafish.

In the human genome, about 750 genes contain one intron excised by the minor spliceosome. This spliceosome comprises its own set of snRNAs, among which U4atac. Its noncoding gene, , has been found mutated in Taybi-Linder (TALS/microcephalic osteodysplastic primordial dwarfism type 1), Roifman (RFMN), and Lowry-Wood (LWS) syndromes.

Gain-of-function variants in the ion channel gene underlie a spectrum of neurodevelopmental disorders.

TRPM3 is a temperature- and neurosteroid-sensitive plasma membrane cation channel expressed in a variety of neuronal and non-neuronal cells. Recently, rare de novo variants in were identified in individuals with developmental and epileptic encephalopathy, but the link between TRPM3 activity and neuronal disease remains poorly understood. We previously reported that two disease-associated variants in TRPM3 lead to a gain of channel function .

Biallelic variants in HECT E3 paralogs, HECTD4 and UBE3C, encoding ubiquitin ligases cause neurodevelopmental disorders that overlap with Angelman syndrome.

Purpose: Pathogenic variants in genes encoding ubiquitin E3 ligases are known to cause neurodevelopmental syndromes. Additional neurodevelopmental disorders associated with the other genes encoding E3 ligases are yet to be identified.

Methods: Chromosomal analysis and exome sequencing were used to identify the genetic causes in 10 patients from 7 unrelated families with syndromic neurodevelopmental, seizure, and movement disorders and neurobehavioral phenotypes.

New insights into -related Joubert syndrome.

Purpose: In this study, we describe the phenotype and genotype of the largest cohort of patients with Joubert syndrome (JS) carrying pathogenic variants on one of the most frequent causative genes, .

Methods: We selected 53 patients with pathogenic variants on , compiled and analysed their clinical, neuroimaging and genetic information and compared it to previous literature.

Results: Developmental delay (motor and language) was nearly constant but patients had normal intellectual efficiency in 74% of cases (20/27 patients) and 68% followed mainstream schooling despite learning difficulties.

Pontocerebellar Hypoplasia Type 1D: A Case Report and Comprehensive Literature Review.

Pontocerebellar hypoplasia (PCH) is an autosomal recessive, neurodegenerative disorder with multiple subtypes leading to severe neurodevelopmental disabilities. PCH type 1 D is linked to alterations in the EXOSC9 gene. EXOSC9 is a component of the RNA exosome, an evolutionarily conserved ribonuclease complex essential for RNA degradation and processing.

Endocannabinoid dysfunction in neurological disease: neuro-ocular DAGLA-related syndrome.

The endocannabinoid system is a highly conserved and ubiquitous signalling pathway with broad-ranging effects. Despite critical pathway functions, gene variants have not previously been conclusively linked to human disease. We identified nine children from eight families with heterozygous, de novo truncating variants in the last exon of DAGLA with a neuro-ocular phenotype characterized by developmental delay, ataxia and complex oculomotor abnormality.

GGPS1 Mutations Cause Muscular Dystrophy/Hearing Loss/Ovarian Insufficiency Syndrome.

Objective: A hitherto undescribed phenotype of early onset muscular dystrophy associated with sensorineural hearing loss and primary ovarian insufficiency was initially identified in 2 siblings and in subsequent patients with a similar constellation of findings. The goal of this study was to understand the genetic and molecular etiology of this condition.

Methods: We applied whole exome sequencing (WES) superimposed on shared haplotype regions to identify the initial biallelic variants in GGPS1 followed by GGPS1 Sanger sequencing or WES in 5 additional families with the same phenotype.