Aberrant splicing contributes to severe alpha-spectrin-linked congenital hemolytic anemia

• Type of Material: Article
• Authors: Patrick G. Gallagher, Yale University; Yelena Maksimova, Yale University; Kimberly Lezon-Geyda, Yale University; Peter E. Newburger, University of Massachusetts; Desiree Medeiros, Kapiolani Medical Center for Women; Robin D. Hanson, Cardinal's Kids Cancer Center; Jennifer Rothman, Duke University; Sara Israels, University of Manitoba; Donna A. Wall, University of Toronto; Robert F. Sidonio Jr, Emory University; Colin Sieff, Harvard Medical School; L. Kate Gowans, Beaumont Children's Hospital; Nupur Mittal, Rush University; Roland Rivera-Santiago, Wistar Institute; David W. Speicher, Wistar Institute; SusanJ. Baserga, Yale University; Vincent P. Schulz, Yale University
• Language: English
• Date: 2019-07-01
• Publisher: American Society for Clinical Investigation
• Publication Version: Final Published Version
• Copyright Statement: © 2019, American Society for Clinical Investigation.
• Final Published Version (URL): http://dx.doi.org/10.1172/JCI127195
• Title of Journal or Parent Work: Journal of Clinical Investigation
• ISSN: 0021-9738
• Volume: 129
• Issue: 7
• Start Page: 2878
• End Page: 2887
• Grant/Funding Information: This work was supported in part by grants from the National Institutes of Health (HL65448, DK106857, DK032094, CA009171, GM115710, and GM122926); and the Arnold J. Alderman family.
• Keywords: HEREDITARY ELLIPTOCYTOSIS; PYROPOIKILOCYTOSIS; MESSENGER-RNA DECAY; Research & Experimental Medicine; Life Sciences & Biomedicine; MUTATION; GENE; WILD-TYPE; DISEASE; ERYTHROCYTE SPECTRIN; DEFICIENCY; Science & Technology; Medicine, Research & Experimental; MEMBRANE SKELETAL PROTEINS
• Research Categories: Biology, Genetics; Health Sciences, Pathology; Health Sciences, Medicine and Surgery

Abstract

The etiology of severe hemolytic anemia in most patients with recessive hereditary spherocytosis (rHS) and the related disorder hereditary pyropoikilocytosis (HPP) is unknown. Whole-exome sequencing of DNA from probands of 24 rHS or HPP kindreds identified numerous mutations in erythrocyte membrane α-spectrin (SPTA1). Twenty-eight mutations were novel, with null alleles frequently found in trans to missense mutations. No mutations were identified in a third of SPTA1 alleles (17/48). WGS revealed linkage disequilibrium between the common rHS-linked αBH polymorphism and a rare intron 30 variant in all 17 mutation-negative alleles. In vitro minigene studies and in vivo splicing analyses revealed the intron 30 variant changes a weak alternate branch point (BP) to a strong BP. This change leads to increased utilization of an alternate 3′ splice acceptor site, perturbing normal α-spectrin mRNA splicing and creating an elongated mRNA transcript. In vivo mRNA stability studies revealed the newly created termination codon in the elongated transcript activates nonsense-mediated decay leading to spectrin deficiency. These results demonstrate that a unique mechanism of human genetic disease contributes to the etiology of a third of rHS cases, facilitating diagnosis and treatment of severe anemia and identifying a new target for therapeutic manipulation.