[1] Salisbury Dist Hosp, Wessex Reg Genet Lab, Salisbury SP2 8BJ, Wilts, England
[2] Univ Southampton, Div Human Genet, Southampton, Hants, England
[3] Kennedy Galton Ctr, N W Thames Reg Genet Serv, Northwick Pk & St Marks NHS Trust, Harrow, Middx, England