Refined genotype-phenotype correlations in neurofibromatosis type 1 patients with point variants.

Background: Neurofibromatosis type 1 (NF1) is one of the most frequent genetic disorders. NF1 is caused by dominant loss-of-function pathogenic variants (PVs) of the tumour-suppressor gene , which encodes neurofibromin, a negative regulator of rat sarcoma proteins. NF1 is an autosomal dominant disorder with complete penetrance, but a highly variable expression.

The Two Faces of Pediatric SCA2.

Introduction: Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant neurological disease usually described in adults. Expanded CAG repeats in the ATXN2 gene can lead to pediatric onset. This study aims to describe the natural history of SCA2 in children.

Loss of function variants in : Connective tissue, Heart defect, thoracic Aortic aneurysm and Neuro developmental Syndrome (CHANS).

Marfan syndrome (MS), Loeys-Dietz syndrome (LDS), and heritable thoracic aortic aneurysms and dissections (hTAAD) are autosomal dominant connective tissue disorders with overlapping clinical features and underlying molecular heterogeneity. While most cases are explained by pathogenic variants in genes involved in extracellular matrix structure or TGFβ signaling, a large proportion of hTAAD cases remain idiopathic. Through exome and genome sequencing in a French diagnostic cohort, we identified rare deleterious variants in in four unrelated individuals with syndromic or isolated vascular disease.

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.

Neurofibromatosis-Noonan syndrome: a prospective monocentric study of 26 patients and literature review.

Background: Data on clinical manifestations of neurofibromatosis-Noonan syndrome (NF-NS) remain heterogeneous, with limited validated descriptions.

Methods: This study aims to better define the clinical and molecular features of NF-NS and compare them with existing literature. Secondary objectives include evaluating inter-rater diagnostic agreement among experienced clinicians and assessing the utility of deep-learning algorithms (Face2Gene [F2G]).

Radial Microbrain (Micrencephaly) Is Caused by a Recurrent Variant in the Gene.

Background And Objectives: Genetic primary microcephaly (PM) is a defect in early brain development leading to congenital microcephaly, mostly recessively inherited, and mild-to-moderate intellectual disability. PM has been largely elucidated, thanks to exome and genome sequencing. However, radial microbrain, the most severe form of genetic PM or micrencephaly described in the 1980s, which leads to early lethality or very severe intellectual handicap, remains without a molecular diagnosis.

Aarskog-Scott syndrome: a clinical study based on a large series of 111 male patients with a pathogenic variant in and management recommendations.

Background: Aarskog-Scott syndrome (AAS) is a rare condition with multiple congenital anomalies, caused by hemizygote variants in the gene. Its description was based mostly on old case reports, in whom a molecular diagnosis was not always available, or on small series. The aim of this study was to better delineate the phenotype and the natural history of AAS and to provide clues for the diagnosis and the management of the patients.

A second RUBCN variant associated with epileptic encephalopathy and neurodevelopmental delay.

The RUBCN gene encodes a widely expressed protein called Rubicon, the main function of which is to negatively regulate macroautophagy. A single homozygous pathogenic variant of the RUBCN gene has been reported to date in two unrelated consanguineous Saudi families with spinocerebellar ataxia autosomal recessive 15 (OMIM#613516). This variant is responsible for the deletion of the highly conserved Rubicon Homology (RH) domain, which is important for the colocalization of Rubicon with Rab7 in the late endosome.

Dominantly acting variants in ATP6V1C1 and ATP6V1B2 cause a multisystem phenotypic spectrum by altering lysosomal and/or autophagosome function.

The vacuolar H-ATPase (V-ATPase) is a functionally conserved multimeric complex localized at the membranes of many organelles where its proton-pumping action is required for proper lumen acidification. The V-ATPase complex is composed of several subunits, some of which have been linked to human disease. We and others previously reported pathogenic dominantly acting variants in ATP6V1B2, the gene encoding the V1B2 subunit, as underlying a clinically variable phenotypic spectrum including dominant deafness-onychodystrophy (DDOD) syndrome, Zimmermann-Laband syndrome (ZLS), and deafness, onychodystrophy, osteodystrophy, intellectual disability, and seizures (DOORS) syndrome.

The expanding clinical and genetic spectrum of DYNC1H1-related disorders.

Intracellular trafficking involves an intricate machinery of motor complexes, including the dynein complex, to shuttle cargo for autophagolysosomal degradation. Deficiency in dynein axonemal chains, as well as cytoplasmic light and intermediate chains, have been linked with ciliary dyskinesia and skeletal dysplasia. The cytoplasmic dynein 1 heavy chain protein (DYNC1H1) serves as a core complex for retrograde trafficking in neuronal axons.

Identification of kinesin family member (KIF22) homozygous variants in spondyloepimetaphyseal dysplasia with joint laxity, lepdodactylic type and demonstration of proteoglycan biosynthesis impairment.

Heterozygous variants in KIF22, encoding a kinesin-like protein, are responsible for spondyloepimetaphyseal dysplasia with joint laxity, leptodactilic type (lepto-SEMDJL), characterized by short stature, flat face, generalized joint laxity with multiple dislocations, and progressive scoliosis and limb deformity. By targeted gene sequencing analysis, we identified a homozygous KIF22 variant (NM_007317.3: c.

Cerebral dural arteriovenous fistulas in patients with PTEN-related hamartoma tumor syndrome.

Central nervous system (CNS) dural arteriovenous fistulas (DAVF) have been reported in PTEN-related hamartoma tumor syndrome (PHTS). However, PHTS-associated DAVF remain an underexplored field of the PHTS clinical landscape. Here, we studied cases with a PTEN pathogenic variant identified between 2007 and 2020 in our laboratory (n = 58), and for whom brain imaging was available.

Germline bi-allelic alteration predisposes to a neonatal juvenile myelomonocytic leukemia-like disorder.

Juvenile myelomonocytic leukemia (JMML) is a rare, generally aggressive myeloproliferative neoplasm affecting young children. It is characterized by granulomonocytic expansion, with monocytosis infiltrating peripheral tissues. JMML is initiated by mutations upregulating RAS signaling.

Biallelic loss of function variants are responsible for neonatal systemic hypertension.

Background: Early-onset isolated systemic hypertension is a rare condition of unknown genetic origin. Renovascular, renal parenchymal diseases or aortic coarctation are the most common causes of secondary systemic hypertension in younger children and neonates. We investigated the genetic bases of early-onset isolated systemic hypertension.

Evaluation of somatic and/or germline mosaicism in congenital malformation of the eye.

Microphthalmia, Anophthalmia and Coloboma (MAC) form a spectrum of congenital eye malformations responsible for severe visual impairment. Despite the exploration of hundreds of genes by High-Throughput Sequencing (HTS), most of the patients remain without genetic diagnosis. One explanation could be the not yet demonstrated involvement of somatic mosaicism (undetected by conventional analysis pipelines) in those patients.

Mitchell-Riley Syndrome: Improving Clinical Outcomes and Searching for Functional Impact of RFX-6 Mutations.

Aims/hypothesis: Caused by biallelic mutations of the gene encoding the transcription factor , the rare Mitchell-Riley syndrome (MRS) comprises neonatal diabetes, pancreatic hypoplasia, gallbladder agenesis or hypoplasia, duodenal atresia, and severe chronic diarrhea. So far, sixteen cases have been reported, all with a poor prognosis. This study discusses the multidisciplinary intensive clinical management of 4 new cases of MRS that survived over the first 2 years of life.

Same performance of exome sequencing before and after fetal autopsy for congenital abnormalities: toward a paradigm shift in prenatal diagnosis?

Prenatal exome sequencing could be complex because of limited phenotypical data compared to postnatal/portmortem phenotype in fetuses affected by multiple congenital abnormalities (MCA). Here, we investigated limits of prenatal phenotype for ES interpretation thanks to a blindly reanalysis of postmortem ES data using prenatal data only in fetuses affected by MCA and harboring a (likely)pathogenic variant or a variant of unknown significance (VUS). Prenatal ES identified all causative variant previously reported by postmortem ES (22/24 (92%) and 2/24 (8%) using solo-ES and trio-ES respectively).

Extending the prenatal Noonan's phenotype by review of ultrasound and autopsy data.

Objectives: The antenatal phenotypic spectrum of Noonan Syndrome (NS) requires better characterization.

Methods: This multicenter retrospective observational included 16 fetuses with molecularly confirmed NS admitted for fetopathological examination between 2009 and 2016.

Results: Among 12 pathogenic variants (PV) in PTPN11 (80%), 5 (42%) fell between position c.