^aDepartment of Clinical Genetics, Yorkshire Regional Genetics Service, Chapel Allerton Hospital

^bDepartment of Cytogenetics, Leeds Genetics Laboratories, Yorkshire Regional Genetics Service, St James’s University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds

^cDepartment of Psychiatry, The Horizon Centre, Fieldhead Hospital, Ouchthorpe Lane, Wakefield, UK

Correspondence to Rosalyn Jewell, MB ChB, PhD, Yorkshire Regional Genetics Service, 3rd Floor, Chapel Allerton Hospital, Chapel Town Road, Leeds LS7 4SA, UK Tel: +44 113 392 4463; fax: +44 113 392 4686; e-mail: [email protected]