title: The intronic ABCA4 c.5461-10T>C variant, frequently seen in patients with Stargardt disease, causes splice defects and reduced ABCA4 protein level.
abstract: OBJECTIVE
  Despite being the third most common ABCA4 variant observed in patients with Stargardt disease, the functional effect of the intronic ABCA4 variant c.5461-10T>C is unknown. The purpose of this study was to investigate the molecular effect of this variant.
  
  
  METHODS
  Fibroblast samples from patients carrying the ABCA4 variant c.5461-10T>C were analysed by isolating total RNA, followed by real-time polymerase chain reaction (RT-PCR) using specific primers spanning the variant. For detection of ABCA4 protein, fibroblast samples were lysed and analysed by SDS-PAGE followed by immunoblotting using a monoclonal ABCA4 antibody.
  
  
  RESULTS
  The ABCA4 variant c.5461-10T>C causes a splicing defect resulting in the reduction of full-length mRNA in fibroblasts from patients and the presence of alternatively spliced mRNAs where exon 39-40 is skipped. A reduced level of full-length ABCA4 protein is observed compared to controls not carrying the variant.
  
  
  CONCLUSIONS
  This study describes the functional effect and the molecular mechanism of the pathogenic ABCA4 variant c.5461-10T>C. The variant is functionally important as it leads to splicing defects and a reduced level of ABCA4 protein.
authors: Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway.
authors: Ingvild
authors: I
authors: Aukrust
authors: Department of Ophthalmology, Haukeland University Hospital, Bergen, Norway.|Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors: Ragnhild W
authors: RW
authors: Jansson
authors: Department of Ophthalmology, Haukeland University Hospital, Bergen, Norway.
authors: Cecilie
authors: C
authors: Bredrup
authors: Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway.
authors: Hilde E
authors: HE
authors: Rusaas
authors: Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway.
authors: Siren
authors: S
authors: Berland
authors: Division of Child and Adolescent Health, Medical Genetics Department, University Hospital of North Norway, Tromsø, Norway.
authors: Agnete
authors: A
authors: Jørgensen
authors: Department of Pathology and Medical Genetics, St. Olav's University Hospital, Trondheim, Norway.
authors: Marte G
authors: MG
authors: Haug
authors: Department of Ophthalmology, Haukeland University Hospital, Bergen, Norway.|Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors: Eyvind
authors: E
authors: Rødahl
authors: Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway.
authors: Gunnar
authors: G
authors: Houge
authors: Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway.|Department of Clinical Science, University of Bergen, Bergen, Norway.
authors: Per M
authors: PM
authors: Knappskog
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics* / Q000378:metabolism; D000328:Adult; D002478:Cells, Cultured; D004252:DNA Mutational Analysis; D004596:Electroretinography; D005091:Exons; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D006801:Humans; D015151:Immunoblotting; D007438:Introns; D008268:Macular Degeneration / Q000151:congenital* / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism; D008297:Male; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D012313:RNA / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D055213:Retinal Pigment Epithelium / Q000378:metabolism / Q000473:pathology; D012374:Rod Cell Outer Segment; D000080362:Stargardt Disease; D041623:Tomography, Optical Coherence; D055815:Young Adult
chemical_list: C056475:ABCA4 protein, human; D018528:ATP-Binding Cassette Transporters; D012313:RNA
keywords: 
  ABCA4
  ; Stargardt; intronic variant; splicing