To report a new form of juvenile-onset Best disease associated with optic disc deposits and autosomal dominant inheritance in a three-generation family.Methods
Five affected individuals aged from 5 to 76 years were assessed. Detailed ophthalmic examination including refraction, color fundus photographs, fundus autofluorescence imaging (FAF), optical coherence tomography (OCT), ISCEV-standard ffERG, mfERG, EOG, as well as ultrasound imaging were performed. Direct sequencing of all exons and intron-exon junction of the BEST1 gene was conducted.Results
The diagnosis of vitelliform maculopathy was confirmed by clinical and electrophysiological findings supported by genetic analysis. Ophthalmic imaging, OCT and ultrasound imaging showed in four out of five affected members deep subretinal deposits in the macula. Unexpected when the macula was affected, deposits located on the surface of the optic disc, showing the same echography and FAF characteristics, were observed. All five subjects had an abnormal EOG and a normal ffERG. The individual mfERG responses measured in the central, but also in the optic disc areas were reduced, the latencies were delayed. Sequencing revealed a heterozygous c.[670 C>A], coding for a L224M mutation in BEST1 in all affected subjects.Conclusion
Through comparison of the morphological tests: OCT, the FAF ultrasound images and the functional measure: mfERG, we deduct that the observed optic disc deposits are part of generalized disease and have the same origin as the subretinal vitelliform macular and multifocal deposits. This suggests that the described optic disc lesions are vitelliform-like optic disc hamartomas.