[1] Royal Hosp Sick Children, Dept Child Hlth, Glasgow G3 8SJ, Lanark, Scotland
[2] Royal Hosp Sick Children, Dept Ophthalmol, Glasgow G3 8SJ, Lanark, Scotland
[3] Royal Hosp Sick Children, Ferguson Smith Ctr Clin Genet, Glasgow G3 8SJ, Lanark, Scotland
[4] Univ London St Bartholomews Hosp Med Coll, Dept Endocrinol, London EC1A 7BE, England