Background/Aim: Bardet-Biedl syndrome is a multi-organ disease presenting with retinitis pigmentosa leading to blindness. The aim of the study was to investigate the genetic background of Bardet-Biedl syndrome in the Faroe Island. We hypothesised that a common genetic background for the syndrome would be found.
Methods: Patients were identified from the files of the Retinitis Pigmentosa Register at the National Eye Clinic, Denmark. The diagnosis of Bardet-Biedl syndrome was verified from medical files. Mutational screening of BBS1, BBS2, BBS4, BBS5, MKKS, and BBS10 was done by denaturing high performance liquid chromatography.
Results: Out of 13 prevalent cases in the Faroe Islands 10 patients from nine families were included. We identified a novel splice site mutation in BBS1, c.1091+3G>C, predicted to affect protein function by skipping of 16 amino acids. Nine patients were homozygous for this mutation while one patient was compound heterozygous with a recurrent BBS1 mutation, p.Met390Arg. The patients presented with severe ophthalmic phenotypes while the systemic manifestations of the disease were apparently milder.
Conclusion: We identified a novel BBS1 mutation, most probably a founder mutation, further confirming the Faroe Islands as a genetic isolate. The phenotypic expression of the Faroese patients suggests that different mutations in BBS1 affect various organs differently.