Biomedical subjects

Jean-Madeleine de Sainte Agathe

Publications and source records attributed to Jean-Madeleine de Sainte Agathe.

3 recordsLinked to original sources

PubMed2026

Characterization of the genotypic and phenotypic spectrum of TCF7L2-related neurodevelopmental disorder (TRND).

PURPOSE: TCF7L2 (OMIM 602228; HGNC:11641) is a transcription factor and a critical effector of the Wnt/ β-Catenin pathway. In 2021, 11 pediatric patients with monoallelic predicted loss-of-function (pLOF) TCF7L2 variants and syndromic features were observed. Characterization of patients with pLOF TCF7L2 variants and neurodevelopmental features-herein referred to as TCF7L2-related neurodevelopmental disorder-is urgently needed. METHODS: We leveraged multiple methods (eg, GeneMatcher, DECIPHER, literature review, and public/private repositories) to identify an international cohort of 76 patients with pLOF TCF7L2 variants and neurodevelopmental features and phenotypically characterized them. We also retrospectively searched for an independent cohort of adults with pLOF TCF7L2 variants (n = 11) from more than 60,000 PennMedicine BioBank patients. RESULTS: Among 76 patients with pLOF TCF7L2 variants, speech delay (95.3%), craniofacial dysmorphisms (73.3%), ophthalmologic conditions (65.5%), autism (62.1%), and orthopedic abnormalities (52.6%) were the most commonly observed. Phenotypic differences did not cluster by variant type or genomic locus. Among PennMedicine BioBank patients, an association of nominal significance with type 2 diabetes with renal manifestations (odds ratio = 5.8; P = .03) was detected, warranting further investigation. CONCLUSION: This study represents the most comprehensive characterization of TCF7L2-related neurodevelopmental disorder to date, a novel neurodevelopmental disorder, defining its genotypic and phenotypic spectra. We opened a Simons Searchlight natural history study that is now available for patient enrollment to enhance the understanding of this condition.

Neurodevelopmental syndrome↗

PubMed2025

Systematic analysis of snRNA genes reveals frequent RNU2-2 variants in dominant and recessive developmental and epileptic encephalopathies.

Variants in spliceosomal small nuclear RNA (snRNA) genes RNU4-2 (ReNU syndrome), RNU5B-1, and RNU2-2 have recently been linked to dominant neurodevelopmental disorders (NDDs), revealing a major, previously overlooked role for noncoding snRNAs in human disease. Here, we systematically analysed 200 potentially functional snRNA genes in a French cohort comprising 26,911 individuals with rare disorders and through international collaborations. We identify de novo and biallelic variants in RNU2-2 associated with both dominant and recessive NDDs in 126 individuals from 108 unrelated families. Recessive RNU2-2 NDD is at least twice as frequent as the dominant NDD caused by n.4G>A and n.35A>G, and often arises from a de novo variant in trans with an inherited allele, reflecting the high mutability of snRNA genes. Dominant and recessive RNU2-2-NDDs share overlapping clinical features with frequent epilepsy. Blood transcriptomics and DNA methylation analyses revealed subtle, variant-specific effects on splicing and episignatures. Our findings support a gradient-of-impact model and a continuum between dominant and recessive inheritance, establishing RNU2-2 variants as a frequent cause of NDDs, nearly as prevalent as ReNU syndrome.

Journal Article↗

PubMed2025

A founder variant in TBCB is associated with global developmental delay, autism spectrum, and spastic paraparesis.

PURPOSE: Hereditary spastic paraparesis (HSP) is a genetically diverse group of Mendelian disorders characterized by length-dependent axonal degeneration. Microtubule dysfunction is a known mechanism in HSP that impairs axonal dynamics. TBCB encodes tubulin-folding cofactor B (TBCB), which, along with TBCE, regulates αβ-heterodimer dynamics and neuronal axonal growth. Here, we describe a new form of complicated HSP caused by a founder variant in TBCB. METHODS: Exome sequencing revealed a homozygous c.589T>A p.(Tyr197Asn) variant in TBCB in a cohort of 10 individuals assembled through genematching tools. Protein function was assessed using Saccharomyces cerevisiae ortholog ALF1, and a CRISPR-Cas9-generated homologous mutant in Drosophila melanogaster. TBCB expression and localization were examined in fibroblasts using western blot and immunofluorescence. RESULTS: Participants displayed late-childhood-onset spastic paraparesis, global developmental delay, and autism spectrum. TBCB protein levels were reduced in affected fibroblasts. The ALF1 mutant in yeast increased benomyl sensitivity, resembling a loss-of-function phenotype. In Drosophila melanogaster, the homologous mutant led to reduced survival and impaired climbing ability. CONCLUSION: We describe a novel neurodevelopmental disorder with spastic paraparesis and a high carrier rate in the Ashkenazi Jewish population. Our results indicate that TBCB has a vital role in the development of central nervous system and potentially in axonal function in humans.

Humans↗