Abstract
Purpose::
To investigate and compare the ocular phenotype and its natural history of patients with Bardet-Biedl Syndrome (BBS), who are carrier of BBS1 mutation to those with BBS10 mutation.
Methods::
Longitudinal ocular function and morphology was assessed in patients with homozygous or compound heterozygous mutation in the BBS 1 and BBS 10. EDTRS visual acuity (VA), ISCEV standard full-field electroretinogram (ERG), refractive error and grade of maculopathy were compared for the two patient groups.
Results::
14 patients (10 females, 4 males) equally divided for BBS1 and BBS10 were included. All except 3 patients with BBS1 mutations were compound heterozygous. Mean follow up time was 9.9 yrs (BBS1) and 5.2 yrs (BBS10). VA loss in BBS1 ranged from 0 to 2.2 lines (mean 0.75) and in BBS10 from 0.3 to 1.5 lines (mean 1.0). 21 ERGs were recorded in 7 patients (BBS1) and 6 (BBS10). ERGs were non-recordable above noise at initial testing in 3/7 between 5.7 and 12 yrs (BBS1) and in 3/6 between 8.1 and 15.2 yrs of age. A rod-cone dysfunction was evident in 4/7 (BBS1) and 3/6 (BBS10). Repeated ERGs in 3/7 (BBS1) and 1/6 (BBS10) demonstrated significant disease progression. A maculopathy was observed in 6/7 (BBS1) and 3/7 (BBS10) patients. Refractive errors varied from +2.5 to -3.5 (BBS1) and +2.5 to -4.0 (BBS10).
Conclusions::
Both patient groups show a similar VA deterioration and progressive rod-done dysfunction. Macular changes seem to be more present among patients with BBS1 mutations, which might be biased by the higher age in this group. The ocular phenotype and the natural history do not differ significantly between patients with BBS1 and patients with BBS10 mutations.
Keywords: retinal degenerations: hereditary • genetics • electrophysiology: clinical