Functional Characterization of a Novel Intronic Variant in PIEZO2 in a Recessive Form of Distal Arthrogryposis With Impaired Proprioception and Touch (DAIPT).

Background: Distal arthrogryposis with impaired proprioception and touch (DAIPT) is a rare autosomal recessive neurological disease characterized by progressive alteration of mechanosensation. DAIPT is caused by loss of function variants in the PIEZO2 gene that encodes an ionic channel involved in mechanotransduction signaling. Our study started from the case of an 11-year-old boy with skeletal and neuromuscular features suggestive of DAIPT.

Genetic Landscape of a Pleural Mesothelioma in a Child Affected by NF2-Related Schwannomatosis.

We report the first case of pleural mesothelioma (PM) occurring in a child affected by NF2-related schwannomatosis (NF2-SWN) and without any history of environmental exposure to asbestos. Mesothelioma is a rare secondary tumor in brain cancer patients and the association with NF2-SWN has been described only in a few anecdotal cases and never in the pediatric field. NF2-SWN is an autosomal dominant disease caused by inactivating germline mutations of the tumor suppressor gene, one of the most common mutations associated with human primary mesothelioma too.

Targeted Re-Sequencing of Neural Tube Defects Patients and Families Identifies Rare Variants in Genes Candidate From Animal Models.

Background/objectives: Neural tube defects (NTDs) are congenital malformations arising when the neural tube (NT), precursor of the brain and spine, fails to properly close during neurulation. Etiology is multifactorial, with environmental and genetic factors variably contributing on a case-by-case basis. Molecular genetic studies of murine NTD genes have been precious in the identification of predisposing NTD genes in humans, highlighting the peculiar role of the planar cell polarity (PCP) pathway in a fraction of human NTD patients.

Arteriovenous cerebral high-flow shunts: genetic analysis of patients from a pediatric tertiary care center.

Introduction: Arteriovenous cerebral high-flow shunts include the vein of Galen aneurysmal malformation (VGAM) and vein of Galen dilatation, which are considered secondary to arteriovenous malformations or arteriovenous fistulas. These entities are often sporadic but are found in association with variants of the and genes (capillary malformation-arteriovenous malformation, CMAVM; OMIM #608354) or and genes (hereditary hemorrhagic telangiectasia, HHT; OMIM #187300). The clinical phenotypes associated with these conditions are highly variable, with incomplete penetrance and mostly dependent on the hemodynamic consequences (including heart failure and cerebral hemorrhage) or management complications rather than anatomical vascular variations .

Novel De Novo RALA Missense Variants Expand the Genotype Spectrum of Hiatt-Neu-Cooper Neurodevelopmental Syndrome.

Background: RALA is a small GTPase from the RAS superfamily implicated in signal transduction and cytoskeletal dynamics. Recently, de novo variants in RALA have been associated with a neurodevelopmental syndrome characterized by intellectual disability (ID), developmental delay (DD), and seizures. So far, only < 12 patients have been reported.

Variants in Chromatin Remodeling Genes Are Involved in Patients With Chiari Malformation Type 1.

Objectives: Chiari malformation type 1 (CMI) is defined by the herniation of cerebellar tonsils of 5 mm or more, with possible neurological consequences, including compression of the neural tissue and/or anomalies in cerebral spinal fluid circulation. The etiology of CMI is not fully elucidated, with both genetic and environmental factors being involved. Several genes and pathways involved in bone development are pointed out like genes of the WNT, FGF, and BMP signaling pathways.

DNA-binding affinity and specificity determine the phenotypic diversity in BCL11B-related disorders.

BCL11B is a Cys2-His2 zinc-finger (C2H2-ZnF) domain-containing, DNA-binding, transcription factor with established roles in the development of various organs and tissues, primarily the immune and nervous systems. BCL11B germline variants have been associated with a variety of developmental syndromes. However, genotype-phenotype correlations along with pathophysiologic mechanisms of selected variants mostly remain elusive.

Expanding the phenotype of UPF3B-related disorder: Case reports and literature review.

UPF3B encodes the Regulator of nonsense transcripts 3B protein, a core-member of the nonsense-mediated mRNA decay pathway, protecting the cells from the potentially deleterious actions of transcripts with premature termination codons. Hemizygous variants in the UPF3B gene cause a spectrum of neuropsychiatric issues including intellectual disability, autism spectrum disorder, attention deficit hyperactivity disorder, and schizophrenia/childhood-onset schizophrenia (COS). The number of patients reported to date is very limited, often lacking an extensive phenotypical and neuroradiological description of this ultra-rare syndrome.

Case Report: Novel biallelic moderately damaging variants in in a patient with cerebellar dysplasia.

Rotatin, encoded by the gene, is a centrosomal protein with multiple, emerging functions, including left-right specification, ciliogenesis, and neuronal migration. Recessive variants in are associated with a neurodevelopmental disorder with microcephaly and malformations of cortical development known as "Microcephaly, short stature, and polymicrogyria with seizures" (MSSP, MIM #614833). Affected individuals show a wide spectrum of clinical manifestations like intellectual disability, poor/absent speech, short stature, microcephaly, and congenital malformations.

Vein of Galen aneurysmal malformation in newborns: a retrospective study to describe a paradigm of treatment and identify risk factors of adverse outcome in a referral center.

Background: Vein of Galen aneurysmal malformation (VGAM) is a rare cerebral vascular malformation associated with significant morbidity and mortality. Newborns with VGAM without adequate treatment may develop rapidly deteriorating high output heart failure (HOHF) and are at risk for severe neurological outcomes.

Objective: To describe the clinical course and management of newborns with VGAM, and identify which echocardiographic and neuroradiologic factors may be associated with severe heart failure at birth and adverse short term outcomes.

Moyamoya Vasculopathy in Neurofibromatosis Type 1 Pediatric Patients: The Role of Rare Variants of .

Neurofibromatosis type 1 (NF1) is a neurocutaneous disorder caused by mutations in gene, coding for neurofibromin 1. NF1 can be associated with Moyamoya disease (MMD), and this association, typical of paediatric patients, is referred to as Moyamoya syndrome (MMS). MMD is a cerebral arteriopathy characterized by the occlusion of intracranial arteries and collateral vessel formation, which increase the risk of ischemic and hemorrhagic events.

CHAMP1-related disorders: pathomechanisms triggered by different genomic alterations define distinct nosological categories.

Loss-of-function variants in CHAMP1 were recently described as cause of a neurodevelopmental disorder characterized by intellectual disability (ID), autism, and distinctive facial characteristics. By exome sequencing (ES), we identified a truncating variant in CHAMP1, c.1858A > T (p.

Clinical and genetic analysis of patients with segmental overgrowth features and somatic mammalian target of rapamycin (mTOR) pathway disruption: Possible novel clinical issues.

Segmental overgrowth syndromes include a group of clinical entities, all characterized by the abundant proliferation of tissues or organs in association with vascular abnormalities. These syndromes show a wide spectrum of severity ranging from limited involvement of only small areas of the body to complex cases with impressive distortions of multiple tissues and organs. It is now clear that somatic mutations in genes of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway (in brief "mTOR pathway") are responsible for such entities.

An example of parenchymal renal sparing in the context of complex malformations due to a novel mutation in the PBX1 gene.

Introduction: PBX1 encodes the pre-B cell leukemia factor 1, a Three Amino acid Loop Extension (TALE) transcription factor crucial to regulate basic developmental processes. PBX1 loss-of-function variants have been initially described in association with renal malformations in both isolated and syndromic forms.

Case Report: Herein, we report a male infant presenting multiple organ malformations (cleidosternal dysostosis, micrognathia, left lung hypoplasia, wide interatrial defect, pulmonary hypertension, total anomalous pulmonary venous return, intestinal malrotation) and carrying the heterozygous de novo c.

Genotype-phenotype spectrum and correlations in Xia-Gibbs syndrome: Report of five novel cases and literature review.

Background: Xia-Gibbs syndrome (XGS) is a rare neurodevelopmental disorder caused by pathogenic variants in the AT-hook DNA-binding motif-containing 1 gene (AHDC1), encoding a protein with a crucial role in transcription and epigenetic regulation, axonogenesis, brain function, and neurodevelopment. AHDC1 variants possibly act through a dominant-negative mechanism and may interfere with DNA repair processes, leading to genome instability and impaired DNA translesion repair. Variants affecting residues closer to the N-terminal are thought to determine a milder phenotype with better cognitive performances.