Directorate Change

Horizon Discovery Group plc

("Horizon" or the "Company")

Directorate Change

Horizon appoints Mr Grahame Cook as a Non-Executive Director

Cambridge, UK, 14 May 2014: Horizon Discovery Group plc (LSE:HZD), the international life science company supplying research tools and services that power genomics research and the development of personalised medicines, today announces the appointment of Mr Grahame Cook as a Non-Executive Director of the Board with immediate effect. Grahame has also been appointed to the Audit Committee, within which he will assume the role of Chairman.

Grahame Cook is an experienced FTSE and AIM non-executive, with extensive experience as an audit committee chairman. With a background in banking, where he has specialised in the life sciences, pharma and biotech sectors, Grahame has over 20 years' experience of M&A, equity capital markets and investor relations.

Grahame started his career at Arthur Andersen, where he qualified as a chartered accountant and worked within audit and corporate investigations. Subsequent positions include UBS, where he was a member of the global investment banking management committee and global head of equity advisory, and WestLB Panmure, where he was joint Chief Executive Officer. Grahame currently sits on a number of boards, chairing four, including Sinclair Pharma plc and Morphogenesis Inc.

Grahame is a graduate of the University of Oxford and remains a member of the ICAEW.

Dr. Ian Gilham, Chairman of Horizon's Board of Directors, commented:"I would like to welcome Grahame to Horizon's Board and I am confident that Grahame's significant financial and audit experience in growth-oriented life sciences companies and track record in international capital markets, corporate transactions and strategy-setting will prove to be highly valuable as Horizon continues to grow internationally in fast growing markets.

Mr. Grahame Cook said: "Horizon is an outstanding, innovative company which is becoming a global leader in translational and personalised medicine. I am pleased to join an exceptional board of directors guiding the Company during this important time in its evolution."

Contacts:

Horizon Discovery Group plc

Dr Darrin M Disley, Chief Executive Officer

Richard Vellacott, Chief Financial Officer and Senior Vice President, Operations

Tel: +44 (0) 1223 655 580

Consilium Strategic Communications (Financial Media and Investor Relations)

Amber Bielecka / Jessica Hodgson / Matthew Neal / Laura Thornton

Tel: +44 (0) 20 3709 5701

Email: [email protected]

Zyme Communications (Trade and Regional Media)

Katie Odgaard

Tel: +44 (0)7787 502 947

Email: [email protected]

Panmure Gordon (UK) Limited (NOMAD)

Corporate Finance: Freddy Crossley / Duncan Monteith / Fred Walsh

Broking: Tom Salvesen

Tel: +44 20 7886 2500

Grahame David Cook, age 57

Current Directorships or Partnerships

Actinopharma Limited

Biocure Limited

Davall Gears Ltd

EPI-V GP Investments LLP

KS Halkins LLP

MDY Healthcare Limited

Medisys America Limited

Medisys Safety Products Limited

Minoan Group plc

Morgan Rossiter Limited

Morphogenesis Inc.

Pirtsemit Limited

Sinclair IS Pharma plc

Previous Directorships or Partnerships (held in the past five years)

Antisoma Development Limited

Antisoma Research Limited

Antisoma Ventures Limited

Australian Vineyards LLP

C5 Capital Limited

Fulcrum Pharma Limited

Kinnerton Street Freehold Limited

Precious Cells International Limited

Sarossa Capital Limited

T and JK Estates LLP

TJK Holdings LLP

Trigen Holdings Limited

Trigen Limited

Non Profit Advisory Boards

Founding member of techMARK Advisory Council

There are no other disclosures required in relation to Rule 17 or paragraph (g) of Schedule 2 of the AIM Rules for Companies.

ENDS

About Horizon Discovery Group plc www.horizondiscovery.com/

Horizon is a revenue-generating life science company supplying research tools to organizations engaged in genomics research and the development of personalized medicines. Horizon has a diverse and international customer base of over 1,000 organizations across nearly 50 countries, including major pharmaceutical, biotechnology and diagnostic companies as well as leading academic research centers. The Company supplies its products and services into multiple markets, estimated to total in excess of £29 billion by 2015.

Horizon's core capabilities are built around its proprietary translational genomics platform, a high-precision and flexible suite of gene editing tools able to alter almost any endogenous gene sequence of human or mammalian cell-lines. Horizon offers over 16,000 products, almost all of which are based on the application of gene editing to generate cell lines that accurately model the disease-causing mutations found in genetically based diseases. These 'patients-in-a-test-tube' are being used by customers to identify the effect of individual or compound genetic mutations on drug activity, patient responsiveness, and resistance, which may lead to the successful prediction of which patient sub-groups will respond to currently available and future drug treatments.

In addition, Horizon provides rAAV, ZFN and CRISPR gene editing tools, custom cell line and in vivo model generation services for research and bioproduction applications, quantitative molecular reference standards, in vivo disease models, contract research and custom screening services and custom shRNA development services and off-the-shelf validated shRNA (through Horizon's partner Sirion).

Horizon is headquartered in Cambridge, UK, and is listed on the London Stock Exchange's AIM market under the ticker "HZD", for further information please visit: www.horizondiscovery.com.