[1] UNIV DUNDEE, NINEWELLS HOSP & MED SCH, DEPT BIOCHEM MED, DUNDEE DD1 9SY, SCOTLAND
[2] UNIV DUNDEE, NINEWELLS HOSP & MED SCH, DEPT PATHOL, DUNDEE DD1 9SY, SCOTLAND
[3] UNIV LONDON UNIV COLL, DEPT GENET & BIOMETRY, GALTON LAB, LONDON NW1 2HE, ENGLAND
[4] UNIV LONDON UNIV COLL, MRC, HUMAN BIOCHEM GENET UNIT, LONDON NW1 2HE, ENGLAND