Transcript Long-Read Sequencing Unveils the Molecular Complexity of a Novel ROGDI Splicing Variant in a Tunisian Family With Kohlschütter-Tönz Syndrome.

Kohlschütter-Tönz Syndrome (KTS) is an ultra-rare autosomal recessive disorder, characterized by a clinical triad: infantile-onset epilepsy, global developmental delay, and amelogenesis imperfecta. KTS is caused by pathogenic variants in ROGDI, encoding a leucine zipper protein of unknown function. Our study characterizes a novel homozygous ROGDI variant (NM_024589.

Pathogenic de novo variants in PPP2R5C cause a neurodevelopmental disorder within the Houge-Janssens syndrome spectrum.

Pathogenic variants resulting in protein phosphatase 2A (PP2A) dysfunction result in mild to severe neurodevelopmental delay. PP2A is a trimer of a catalytic (C) subunit, scaffolding (A) subunit, and substrate binding/regulatory (B) subunit, encoded by 19 different genes. De novo missense variants in PPP2R5D (B56δ) or PPP2R1A (Aα) and de novo missense and loss-of-function variants in PPP2CA (Cα) lead to syndromes with overlapping phenotypic features, known as Houge-Janssens syndrome (HJS) types 1, 2, and 3, respectively.

Advocating a specific risk calculation of trisomy 18 in case of low maternal serum markers during screening for fetal Down syndrome.

Background: In France, legislation concerning pregnancy monitoring only considers screening for Down syndrome (T21), while the contingent introduction of the circulating cell free DNA test (DPNI) also allows screening for trisomies 13 and 18 with similar performances.

Methods: We retrospectively studied more than 800,000 patients among whom 7971 presented serum markers suggestive of T18 (but without increased risk of T21), of which 438 benefited from NIPT and of a complete pregnancy follow-up.

Results: We show that the use of a specific risk calculation for T18 would have improve the relevance of the prescription.

Novel Digital Anomalies, Hippocampal Atrophy, and Mutations Expand the Genotypic and Phenotypic Spectra of CNKSR2 in the Houge Type of X-Linked Syndromic Intellectual Development Disorder (MRXSHG).

The Houge type of X-linked syndromic intellectual developmental disorder (MRXSHG) encompasses a spectrum of neurodevelopmental disorders characterized by intellectual disability (ID), language/speech delay, attention issues, and epilepsy. These conditions arise from hemizygous or heterozygous deletions, along with point mutations, affecting CNKSR2, a gene located at Xp22.12.

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 only been described in six individuals carrying five biallelic predicted loss of function (pLOF) variants.

-related disorder in 87 adults: Natural history and self-sustainability.

Purpose: is one of the most frequently mutated genes in intellectual disability cohorts. Thus, far few adult-aged patients with -related disorder have been described, which limits our understanding of the disease's natural history and our ability to counsel patients and their families.

Methods: Data on patients aged 18+ years with -related disorder were collected through an online questionnaire completed by clinicians and parents.

Mobile Element Insertion in the APOB Exon 3 Coding Sequence: A New Challenge in Hypobetalipoproteinemia Diagnosis.

Mobile elements (ME) can transpose by copy-and-paste mechanisms. A heterozygous insertion in APOB exon 3 coding sequence was suspected in a patient with hypobetalipoproteinemia (HBL), by gel electrophoresis of the PCR products. An insertion of a 85 bp fragment flanked by a polyA stretch and a target replication site duplication was identified as a ME insertion (MEI) from the AluYa5 subfamily, NM_000384.

Neurodevelopmental Disorder Caused by Deletion of , a lncRNA Gene.

encodes a human long noncoding RNA (lncRNA) adjacent to , a coding gene in which de novo loss-of-function variants cause developmental and epileptic encephalopathy. Here, we report our findings in three unrelated children with a syndromic, early-onset neurodevelopmental disorder, each of whom had a de novo deletion in the locus. The children had severe encephalopathy, shared facial dysmorphisms, cortical atrophy, and cerebral hypomyelination - a phenotype that is distinct from the phenotypes of patients with haploinsufficiency.

Clinical and genetic delineation of autosomal recessive and dominant ACTL6B-related developmental brain disorders.

Purpose: This study aims to comprehensively delineate the phenotypic spectrum of ACTL6B-related disorders, previously associated with both autosomal recessive and autosomal dominant neurodevelopmental disorders. Molecularly, the role of the nucleolar protein ACTL6B in contributing to the disease has remained unclear.

Methods: We identified 105 affected individuals, including 39 previously reported cases, and systematically analyzed detailed clinical and genetic data for all individuals.

Expanding the Mutational Landscape and Clinical Phenotype of CHD2-Related Encephalopathy.

Objectives: To present a case series of novel variants in patients presenting with genetic epileptic and developmental encephalopathy.

Background: CHD2 gene encodes an ATP-dependent enzyme, chromodomain helicase DNA-binding protein 2, involved in chromatin remodeling. Pathogenic variants in CHD2 are linked to early-onset conditions such as developmental and epileptic encephalopathy, drug-resistant epilepsies, and neurodevelopmental disorders.

Expectations, needs and mid-term outcomes in people accessing to secondary findings from ES: 1st French mixed study (FIND Study).

Generation and subsequently accessibility of secondary findings (SF) in diagnostic practice is a subject of debate around the world and particularly in Europe. The French FIND study has been set up to assess patient/parent expectations regarding SF from exome sequencing (ES) and to collect their real-life experience until 1 year after the delivery of results. 340 patients who had ES for undiagnosed developmental disorders were included in this multicenter mixed study (quantitative N = 340; qualitative N = 26).

Loss of heterozygosity in CCM2 cDNA revealing a structural variant causing multiple cerebral cavernous malformations.

Loss-of-function variants in CCM1/KRIT1, CCM2/MGC4607, and CCM3/PDCD10 genes are identified in the vast majority of familial cases with multiple cerebral cavernous malformations. However, genomic DNA sequencing combined with large rearrangement screening fails to detect a pathogenic variant in 5% of the patients. We report a family with two affected members harboring multiple CCM lesions, one with severe hemorrhages and one asymptomatic.

Whole F8 gene sequencing identified pathogenic structural variants in the remaining unsolved patients with severe hemophilia A.

Background: No F8 genetic abnormality is detected in approximately 1% to 2% of patients with severe hemophilia A (HA) using conventional genetic approaches. In these patients, deep intronic variation or F8 disrupting genomic rearrangement could be causal.

Objectives: The study aimed to identify the causal variation in families with a history of severe HA for whom genetic investigations failed.