Site Visit

Horizon Discovery

("Horizon" or the "Group")

Site Visit

Cambridge, UK, 23 February 2017: Horizon Discovery Group plc (LSE: HZD), the world leader in the application of gene editing technologies, is hosting a site visit at its corporate headquarters for institutional investors today and for sell-side analysts on 1st March 2017.

The visits will include a tour of Horizon's new headquarters following the consolidation of the Group's Boston operations, which has created a world class Centre of Excellence in gene editing and cell biology, while also providing a significant contribution towards Horizon's Path to Profit strategy.

During the visit, attendees will hear about the Group's businesses, markets and strategy. No price sensitive information will be disclosed. The presentations will be available on the Group's website on 2nd March 2017.

Hosting the events will be Dr. Darrin Disley, Chief Executive Officer; Richard Vellacott, Chief Financial Officer; Terry Pizzie, Head of Commercial; Dr. Chris Lowe, Head of Research Operations; and Chris Claxton, VP Investor Relations.

For further information, please contact:

Horizon Discovery Group plc

Darrin Disley, Chief Executive Officer

Richard Vellacott, Chief Financial Officer

Chris Claxton, VP Investor Relations

Tel: +44 (0) 1223 655 580

Consilium Strategic Communications (Financial Media and Investor Relations)

Mary-Jane Elliott / Susan Stuart / Matthew Neal / Melissa Gardiner

Tel: +44 (0) 20 3709 5701

Email: [email protected]

About Horizon Discovery Group plc www.horizondiscovery.com

Horizon Discovery Group plc (LSE: HZD) ("Horizon"), is a world-leading gene editing company that designs and engineers genetically-modified cells and then applies them in research and clinical applications that advance human health.

Horizon's core capabilities are built around its proprietary translational genomics platform, a highly precise and flexible suite of gene editing tools (rAAV, ZFN and CRISPR) able to alter almost any gene sequence in human or mammalian cell-lines.

Horizon offers over 23,000 catalogue products and related research services, almost all of which are based on the generation and application of cell and animal models that accurately recapitulate the disease-causing genetic anomalies found in diseases like cancer. Horizon's commercial offering has been adopted by c. 1,600 unique research organisations in over 50 countries as well as in the Company's own R&D pipeline to support a greater understanding of the genetic drivers of disease and the development of molecular, cell and gene therapies that can be prescribed on a personalised basis.

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