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P. Ferraresi et al.
ing factors. This opportunity has been exploited to induce both exon skipping for therapeutic purposes47,48 and to dissect splicing regulatory elements by masking them.20,22,49 In our study, the observation that antisense U7smOPT variants masking the cryptic 5’ss were able to rescue the splicing pattern further demonstrated the path- ogenic role of the nucleotide changes and provided a cor- rection approach that has potential therapeutic implica- tions for the c.571+78A mutation. In fact, if translated into patients, the correct transcripts rescued for this muta- tion (a well-represented change in our patient cohort and associated with severe forms) would account for FVII lev- els well beyond the therapeutic threshold.
In conclusion, the combination of NGS of the entire F7 gene with the expression of minigenes elucidated the molecular bases of FVII deficiency in ten out of thirteen
FVII deficient patients, thus improving diagnosis and genetic counselling, and provided insight into a potential therapeutic approach based on antisense technology, suc- cessfully exploited in other disorders.
Acknowledgments
The authors would like to thank Dr D. Schümperli for sharing the U7-SmOPT construct. This research was supported by grants from Bayer (2017-INT.A-BD_001 to D.Balestra), the University of Ferrara and the University of Montpellier. The authors gratefully acknowledge H. Chambost, K. Pouymayou (Marseille), S. Clayssens (Toulouse), R. D’Oiron, I. Martin- Toutain (Paris), V. Gay (Chambery), Y. Chevalier, S Le- Quellec, S. Meunier, L. Rugeri (Lyon), C. Montaud (Pau) and R. Navarro (Montpellier, France) for sending samples and L.Bison for technical assistance.
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