Total Voting Rights

9 October 2018

Horizon Discovery Group plc 

Total Voting Rights

In accordance with Disclosure and Transparency Rule 5.6.1 Horizon Discovery Group plc (the "Company") advises that:

As at 28 September 2018, the Company's issued share capital consisted of 149,997,647 ordinary shares of 1p each with voting rights. The Company does not hold any ordinary shares in Treasury.

The total number of voting rights in the Company is therefore 149,997,647.

The above figure (149,997,647) may be used by shareholders as the denominator for the calculations by which they will determine if they are required to notify their interest in, or a change to their interest in, Horizon Discovery Group plc under the FCA's Disclosure and Transparency Rules.

ENDS

For further information, please contact:

Horizon Discovery Group plc

Terry Pizzie, Chief Executive Officer

Richard Vellacott, Chief Financial Officer

Tel: +44 (0) 1223 655 580

Consilium Strategic Communications (Financial Media and Investor Relations)

Mary-Jane Elliott / Matthew Neal / Melissa Gardiner

Tel: +44 (0) 20 3709 5701

Email: [email protected]

Numis Securities Limited (Broker and NOMAD)

Michael Meade / Freddie Barnfield

Tel: +44 (0) 207 260 1000

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 delivers inspired cell solutions using its translational genomics platform, a highly precise and flexible suite of DNA editing (rAAV, ZFN, CRISPR and Transposon) and modulation (RNAi, cDNA and 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 personalized molecular, cell and gene therapies. These have been adopted by over 10,000 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".