Deep-intronic ABCA4 variants explain missing heritability in Stargardt disease and allow correction of splice defects by antisense oligonucleotides

Riccardo Sangermano, Alejandro Garanto, Mubeen Khan, Esmee H. Runhart, Miriam Bauwens, Nathalie M. Bax, L. Ingeborgh van den Born, Muhammad Imran Khan, Stéphanie S. Cornelis, Joke B.G.M. Verheij, Jan Willem R. Pott, Alberta A.H.J. Thiadens, Caroline C.W. Klaver, Bernard Puech, Isabelle Meunier, Sarah Naessens, Gavin Arno, Ana Fakin, Keren J. Carss, F. Lucy RaymondAndrew R. Webster, Claire Marie Dhaenens, Heidi Stöhr, Felix Grassmann, Bernhard H.F. Weber, Carel B. Hoyng, Elfride De Baere, Silvia Albert, Rob W.J. Collin*, Frans P.M. Cremers*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

92 Citations (Scopus)


Purpose: Using exome sequencing, the underlying variants in many persons with autosomal recessive diseases remain undetected. We explored autosomal recessive Stargardt disease (STGD1) as a model to identify the missing heritability. Methods: Sequencing of ABCA4 was performed in 8 STGD1 cases with one variant and p.Asn1868Ile in trans, 25 cases with one variant, and 3 cases with no ABCA4 variant. The effect of intronic variants was analyzed using in vitro splice assays in HEK293T cells and patient-derived fibroblasts. Antisense oligonucleotides were used to correct splice defects. Results: In 24 of the probands (67%), one known and five novel deep-intronic variants were found. The five novel variants resulted in messenger RNA pseudoexon inclusions, due to strengthening of cryptic splice sites or by disrupting a splicing silencer motif. Variant c.769-784C>T showed partial insertion of a pseudoexon and was found in cis with c.5603A>T (p.Asn1868Ile), so its causal role could not be fully established. Variant c.4253+43G>A resulted in partial skipping of exon 28. Remarkably, antisense oligonucleotides targeting the aberrant splice processes resulted in (partial) correction of all splicing defects. Conclusion: Our data demonstrate the importance of assessing noncoding variants in genetic diseases, and show the great potential of splice modulation therapy for deep-intronic variants.

Original languageEnglish
Pages (from-to)1751-1760
Number of pages10
JournalGenetics in Medicine
Issue number8
Early online date15 Jan 2019
Publication statusPublished - Aug 2019


  • ABCA4
  • antisense oligonucleotide
  • deep-intronic variant
  • missing heritability
  • Stargardt disease


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