Biomedical subjects

Ortal Barel

Publications and source records attributed to Ortal Barel.

3 recordsLinked to original sources

PubMed2026

Further Support for Association of DAND5 with Autosomal Recessive Laterality Disorders.

BACKGROUND: Laterality defects are rare congenital malformations that encompass congenital heart defects (CHDs) together with abnormalities of visceral organ arrangement (situs inversus or situs ambiguous). These defects may be isolated or part of a syndromic presentation with multisystem involvement. While over 50 genes have been implicated in laterality disorders, across multiple modes of inheritance, many cases remain molecularly undiagnosed. We sought to elucidate the molecular basis of dextrocardia, CHDs and visceral heterotaxy in two unrelated individuals of Arab-Muslim descent. METHODS: Detailed clinical phenotyping and exome sequencing (ES) were performed for each of the probands, followed by familial segregation analysis. RESULTS: ES revealed a shared homozygous variant in the Dan Domain Family Member 5 (DAND5) gene (NM_152654.3): c.396_397dup, p.(Tyr133SerfsTer11). DAND5 encodes a member of the Cerberus-related DAN protein family, which is involved in the establishment of left body asymmetry. This frameshift variant introduces a premature stop codon within the final exon, which is predicted to escape nonsense-mediated decay (NMD), resulting in a truncated protein lacking the functional DAN domain. CONCLUSIONS: DAND5 has recently been suggested as a candidate gene in heterotaxy and CHDs. Our findings further support biallelic loss of function variants in DAND5 autosomal recessive laterality defects.

Female↗

PubMed2025

RELA Haploinsufficiency Manifesting as an Atypical Phenotype of Crohn's Disease.

BACKGROUND: Mutations in RELA, a key component of NF-κB signaling, are associated with dysregulated immune responses and inflammatory disorders. While immunodeficiency phenotypes associated with RELA haploinsufficiency have been reported, gastrointestinal manifestations remain poorly described. This study aimed to characterize the clinical, genomic, and immunological features of a patient presenting with an atypical Crohn's-like phenotype driven by RELA haploinsufficiency. METHODS: Whole-exome sequencing was performed, and results were confirmed by Sanger sequencing. Protein modeling, Western blotting, immunofluorescence, and nuclear extract-based NF-κB activation assays were conducted to assess the functional impact of the identified variant. Immune profiling was performed using mass cytometry time of flight (CyTOF) and single-cell RNA sequencing (scRNA-seq) and compared to controls. RESULTS: We studied a 17-year-old male diagnosed with pan-enteric Crohn's disease (CD), perianal fistulas, chronic mucocutaneous candidiasis, and chronic lymphopenia. Sequencing identified a heterozygous missense variant in RELA (c.587T>C, p.V196A) that potentially impairs RelA (p65) protein stability, confirmed by reduced activity and diminished protein expression. CyTOF analysis revealed decreased circulating T regulatory cells (Tregs), absence of mucosal Tregs, high apoptotic rates, and elevated IFN-γ induced levels, while scRNA-seq demonstrated a robust type I/II interferon signature in multiple immune subsets. Dysregulated mucosal-associated invariant T (MAIT) and cytotoxic CD4+ T cells exhibited upregulation of IL23R and ADAM12, further linking RELA dysfunction to enhanced pro-inflammatory T cell response and tissue inflammation. CONCLUSION: This study links RELA haploinsufficiency with CD-like features, Th1/Th17 polarization, and interferon-driven inflammation, emphasizing the importance of genetic evaluation in patients with atypical or refractory IBD.

Humans↗

PubMed2024

Loss-of-function in RBBP5 results in a syndromic neurodevelopmental disorder associated with microcephaly.

PURPOSE: Epigenetic dysregulation has been associated with many inherited disorders. RBBP5 (HGNC:9888) encodes a core member of the protein complex that methylates histone 3 lysine-4 and has not been implicated in human disease. METHODS: We identify 5 unrelated individuals with de novo heterozygous variants in RBBP5. Three nonsense/frameshift and 2 missense variants were identified in probands with neurodevelopmental symptoms, including global developmental delay, intellectual disability, microcephaly, and short stature. Here, we investigate the pathogenicity of the variants through protein structural analysis and transgenic Drosophila models. RESULTS: Both missense p.(T232I) and p.(E296D) variants affect evolutionarily conserved amino acids located at the interface between RBBP5 and the nucleosome. In Drosophila, overexpression analysis identifies partial loss-of-function mechanisms when the variants are expressed using the fly Rbbp5 or human RBBP5 cDNA. Loss of Rbbp5 leads to a reduction in brain size. The human reference or variant transgenes fail to rescue this loss and expression of either missense variant in an Rbbp5 null background results in a less severe microcephaly phenotype than the human reference, indicating both missense variants are partial loss-of-function alleles. CONCLUSION: Haploinsufficiency of RBBP5 observed through de novo null and hypomorphic loss-of-function variants is associated with a syndromic neurodevelopmental disorder.

Humans↗