Annual Report and Notice of Annual General Meeting

Horizon Discovery Group plc

Annual Report and Notice of Annual General Meeting

Cambridge, UK, 21 May 2019: Horizon Discovery Group plc (LSE: HZD) ("Horizon" or "the Company"), a global leader in the application of gene editing and gene modulation technologies, announces that its annual report and accounts for the year ended 31 December 2018, which includes the notice convening the Company's 2019 Annual General Meeting (AGM), will be posted to shareholders today.

The 2019 annual report and accounts and notice of AGM will be available on the Investor Relations section of the Company's website at www.horizondiscovery.com from 17.00 BST today.

Horizon's AGM will be held on Tuesday, 18 June 2018 and will take place at the Company's offices ‐ Building 8100 Cambridge Research Park, Waterbeach, Cambridge, CB25 9TL, commencing at 12.00 noon BST.

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For further information from Horizon Discovery Group plc, please contact:

Horizon Discovery Group plc

Terry Pizzie, Chief Executive Officer

Jayesh Pankhania, Chief Financial Officer

Jon Davies, Head of Investor Relations

Tel: +44 (0) 1223 655 580

Numis Securities Limited (Broker and NOMAD)

James Black / Freddie Barnfield / Duncan Monteith

Tel: +44 (0) 207 260 1000

Consilium Strategic Communications (Financial Media and Investor Relations)

Mary-Jane Elliott / Matthew Neal / Melissa Gardiner

Tel: +44 (0) 20 3709 5700

Email: [email protected]

About Horizon Discovery Group plc www.horizondiscovery.com

Horizon Discovery Group plc (LSE: HZD) ("Horizon") is a world leader in gene editing and gene modulation technologies. Horizon designs and engineers cells using its translational genomics platform, a highly precise and flexible suite of DNA editing tools (rAAV, ZFN, CRISPR, Transposon and base editing) and, following the acquisition of Dharmacon, Inc., its functional genomics platform comprising gene knockdown (RNAi) and gene expression (cDNA, ORF) tools, for research and clinical applications that advance human health. Horizon's platforms and capabilities enable researchers to alter almost any gene or modulate its function in human or mammalian cell-lines.

Horizon offers an extensive range of catalogue products and related research services to support a greater understanding of the function of genes across all species and the genetic drivers of human disease and the development of personalised molecular, cell and gene therapies. These have been adopted by academic, drug discovery, drug manufacturing and clinical diagnostics customers around the globe, as well as in the Company's own R&D pipeline.

Horizon is headquartered in Cambridge, UK, and is listed on the London Stock Exchange's AIM market under the ticker HZD.