An AAV Dual Vector Strategy Ameliorates the Stargardt Phenotype in Adult Abca4-/- Mice

Michelle E. McClements, Alun R. Barnard, Mandeep S. Singh, Peter Charbel Issa, Zhichun Jiang, Roxana A. Radu, Robert E. MacLaren

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


The recent approval in the United States of the first adeno-associated viral (AAV) vector for the treatment of an inherited retinal degeneration validates this approach for the treatment of many other diseases. A major limiting factor continues to be the size restriction of the AAV transgene at under 5 kb. Stargardt disease is the most prevalent form of recessively inherited blindness and is caused by mutations in ABCA4, the gene that codes for ATP-binding cassette transporter protein family member 4, which has a coding sequence length of 6.8 kb. Dual vector approaches increase the capacity of AAV gene therapy, but at the cost of substantially reduced levels of target protein, which may be insufficient to achieve a therapeutic effect. Here we show that the efficacy of recombination of dual vectors is dependent on the length of DNA overlap between two transgenes. With optimized recombination, full-length ABCA4 protein is expressed in the photoreceptor outer segments of Abca4-/- mice at levels sufficient to reduce bisretinoid formation and correct the autofluorescent phenotype. These observations support a dual vector approach in future clinical trials using AAV gene therapy to treat Stargardt disease.

Original languageEnglish (US)
Pages (from-to)590-600
Number of pages11
JournalHuman gene therapy
Issue number5
StatePublished - May 2019


  • ABCA4
  • Stargardt disease
  • adeno-associated virus
  • dual vector
  • gene therapy

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology
  • Genetics


Dive into the research topics of 'An AAV Dual Vector Strategy Ameliorates the Stargardt Phenotype in Adult Abca4-/- Mice'. Together they form a unique fingerprint.

Cite this