Identification of a de novo splicing variant in the Coffin-Siris gene, SMARCE1, in a patient with Angelman-like syndrome

Aguilera, Cinthia; Gabau, Elisabeth; Laurie, Steven, 1973-; Baena, Neus; Derdak, Sophia; Capdevila, Núria; Ramirez, Ariadna; Delgadillo, Veronica; García-Catalan, Maria Jesus; Brun i Gasca, Carme; Guitart, Miriam; Ruiz, Anna

doi:http://dx.doi.org/10.1002/mgg3.511

Identification of a de novo splicing variant in the Coffin-Siris gene, SMARCE1, in a patient with Angelman-like syndrome

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Aguilera C, Gabau E, Laurie S, Baena N, Derdak S, Capdevila N, Ramirez A, Delgadillo V, García-Catalan MJ, Brun C, Guitart M, Ruiz A. Identification of a de novo splicing variant in the Coffin-Siris gene, SMARCE1, in a patient with Angelman-like syndrome. Mol Genet Genomic Med. 2019; 7(1):e00511. DOI 10.1002/mgg3.511

Abstract

Background: Patients affected by Angelman syndrome (AS) present severe intellectual disability, lack of speech, ataxia, seizures, abnormal electroencephalography (EEG), and a characteristic behavioral phenotype. Around 10% of patients with a clinical diagnosis of AS (AS‐like) do not have an identifiable molecular defect. Some of these patients harbor alternative genetic defects that present overlapping features with AS. Methods: Trio whole‐exome sequence was performed on patient and parent's DNA extracted from peripheral blood. Exome data were filtered according to a de novo autosomal dominant inheritance. cDNA analysis was carried out to assess the effect of the splice site variant. Results: We identified a novel heterozygous SMARCE1 splicing variant that leads to an exon skipping in a patient with an Angelman‐like phenotype. Missense variants in the SMARCE1 gene are known to cause Coffin–Siris syndrome (CSS), which is a rare congenital syndrome. Clinical reevaluation of the patient confirmed the presence of characteristic clinical features of CSS, many of them overlapping with AS. Conclusions: Taking into account the novel finding reported in this study, we consider that CSS should be added to the expanding list of differential diagnoses for AS.