Mol Genet Genomic Med
Henan Key Laboratory of Children's Genetics and Metabolic Diseases, Children's Hospital Affiliated to Zhengzhou University, Henan Children's Hospital Zhengzhou Children's Hospital, Zhengzhou, Henan, China.
Published: May 2024
Background: Cornelia de Lange syndrome (CdLS) is a multisystem genetic disorder, and cases caused by variants in the structural maintenance of chromosomes protein 3 (SMC3) gene are uncommon. Here, we report two cases of CdLS associated with novel pathogenic variants in SMC3 from two Chinese families.
Methods: Clinical presentations of two patients with CdLS were evaluated, and specimens from the patients and other family members were collected for Trio-based whole-exome sequencing. Pyrosequencing, chip-based digital PCR, minigene splicing assay, and in silico analysis were carried out to elucidate the impact of novel variants.
Results: Novel heterozygous variants in SMC3 were identified in each proband. One harbored a novel splicing and mosaic variant (c.2535+1G>A) in SMC3. The mutated allele G>A conversion was approximately 23.1% by digital PCR, which indicated that 46.2% of peripheral blood cells had this variant. Additionally, in vitro minigene splicing analysis validated that the c.2535+1G>A variant led to an exon skipping in messenger RNA splicing. The other carried a heterozygous variant (c.435C>A), which was predicted to be pathogenic as well as significantly altered in local electrical potential. The former showed multiple abnormalities and marked clinical severity, and the latter mainly exhibited a speech developmental disorder and slightly facial anomalies.
Conclusion: Both patients were clinically diagnosed with Cornelia de Lange syndrome 3 (CdLS3). The newly identified SMC3 gene variants can expand the understanding of CdLS3 and provide reliable evidence for genetic counseling to the affected family.
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http://dx.doi.org/10.1002/mgg3.2447 | DOI Listing |
Cells
December 2024
Institute for Biomedical Technologies, National Research Council, 56124 Pisa, Italy.
Cornelia de Lange syndrome (CdLS) is a rare, dominantly inherited multisystem developmental disorder. Pathogenic variants in genes encoding the structural subunits and regulatory proteins of the cohesin complex (, , , , and ) are the primary contributors to the pathogenesis of CdLS. Pathogenic variations in these genes disrupt normal cohesin function, leading to the syndrome's diverse and complex clinical presentation.
View Article and Find Full Text PDFGenes (Basel)
September 2024
Medical and Laboratory Genetics Unit, A.O.R.N. "Antonio Cardarelli", 80131 Naples, Italy.
SAGE Open Med Case Rep
August 2024
Department of Molecular and Medical Genetics, Tbilisi State Medical University, Tbilisi, Georgia.
The cohesin protein complex plays a vital role in various cellular processes such as sister chromatid cohesion, chromosome condensation, DNA repair, and transcriptional regulation. It is constituted by SMC1, SMC3, RAD21, STAG1/STAG2 subunits, and several regulatory proteins. Pathogenic variants in these components cause cohesinopathies, with common clinical features including facial dysmorphism, delayed growth, developmental delay, and limb anomalies.
View Article and Find Full Text PDFExp Mol Med
August 2024
Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences; ENT Institute, Department of Facial Plastic and Reconstructive Surgery, Eye & ENT Hospital; Institute of Medical Genetics & Genomics; Key Laboratory of Birth Defects, Children's Hospital; Medical Science Data Center at Intelligent Medicine Institute, Fudan University, Shanghai, 200032, China.
Development
August 2024
Department of Pathology, Dunedin School of Medicine, University of Otago, P.O. Box 913, Dunedin 9016, New Zealand.
Cohesin, a chromatin-associated protein complex with four core subunits (Smc1a, Smc3, Rad21 and either Stag1 or 2), has a central role in cell proliferation and gene expression in metazoans. Human developmental disorders termed 'cohesinopathies' are characterized by germline variants of cohesin or its regulators that do not entirely eliminate cohesin function. However, it is not clear whether mutations in individual cohesin subunits have independent developmental consequences.
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