^aDepartment of Medicine, Nottingham City Hospital, Hucknall Road, Nottingham

^bSouth East of Scotland Clinical Genetics Service, Western General Hospital, Edinburgh, UK

Correspondence to Dr Andrew G.L. Douglas, MB ChB, Wessex Clinical Genetics Service, Princess Anne Hospital, Coxford Road, Southampton SO16 5YA, UK

Tel: +44 23 8079 6170; fax: +44 23 8079 4346; e-mail: [email protected]

Received 30 July 2009 Accepted 11 August 2009