New Cases and Mutations in SEC23B Gene Causing Congenital Dyserythropoietic Anemia Type II

Autor: Melina Mara Musri, Veronica Venturi, Xènia Ferrer-Cortès, Lídia Romero-Cortadellas, Gonzalo Hernández, Pilar Leoz, María Pilar Ricard Andrés, Marta Morado, María del Carmen Fernández Valle, David Beneitez Pastor, Ana Ortuño Cabrero, Maite Moreno Gamiz, Leonor Senent Peris, Amanda Isabel Perez-Valencia, Santiago Pérez-Montero, Cristian Tornador, Mayka Sánchez
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: International Journal of Molecular Sciences, Vol 24, Iss 12, p 9935 (2023)
Druh dokumentu: article
ISSN: 1422-0067
1661-6596
DOI: 10.3390/ijms24129935
Popis: Congenital dyserythropoietic anemia type II (CDA II) is an inherited autosomal recessive blood disorder which belongs to the wide group of ineffective erythropoiesis conditions. It is characterized by mild to severe normocytic anemia, jaundice, and splenomegaly owing to the hemolytic component. This often leads to liver iron overload and gallstones. CDA II is caused by biallelic mutations in the SEC23B gene. In this study, we report 9 new CDA II cases and identify 16 pathogenic variants, 6 of which are novel. The newly reported variants in SEC23B include three missenses (p.Thr445Arg, p.Tyr579Cys, and p.Arg701His), one frameshift (p.Asp693GlyfsTer2), and two splicing variants (c.1512-2A>G, and the complex intronic variant c.1512-3delinsTT linked to c.1512-16_1512-7delACTCTGGAAT in the same allele). Computational analyses of the missense variants indicated a loss of key residue interactions within the beta sheet and the helical and gelsolin domains, respectively. Analysis of SEC23B protein levels done in patient-derived lymphoblastoid cell lines (LCLs) showed a significant decrease in SEC23B protein expression, in the absence of SEC23A compensation. Reduced SEC23B mRNA expression was only detected in two probands carrying nonsense and frameshift variants; the remaining patients showed either higher gene expression levels or no expression changes at all. The skipping of exons 13 and 14 in the newly reported complex variant c.1512-3delinsTT/c.1512-16_1512-7delACTCTGGAAT results in a shorter protein isoform, as assessed by RT-PCR followed by Sanger sequencing. In this work, we summarize a comprehensive spectrum of SEC23B variants, describe nine new CDA II cases accounting for six previously unreported variants, and discuss innovative therapeutic approaches for CDA II.
Databáze: Directory of Open Access Journals
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