Bardet-Biedl syndrome is a ciliopathy mainly associated with retinal dystrophy, renal dysfunction, post-axial polydactyly, obesity, cognitive deficit and hypogonadism. The symptoms associated with retinal dystrophy do not usually appear until the first decade of life, so the diagnosis is usually delayed. Ocular involvement may be the initial form of manifestation of this syndrome, it may even be the only one, so it should be taken into account in the differential diagnosis of amblyopia in a child who does not improve despite correct compliance with treatment. A case of low visual acuity in a pediatric patient is presented as an initial manifestation that leads to the diagnosis of Bardet-Biedl Syndrome, and which is also the only symptom that the patient presents to date, despite being a multisystem disease.

OBJECTIVE: Our objective is to describe a multifocal vitelliform presentation of Best\'s disease. The lesions in this disease may vary in size and shape, some may be a disc diameter in size, and often have some irregularity in their contour. The case is described of a 21-year-old male patient referred to our ophthalmology department due to a progressive loss of vision. His poor visual acuity was confirmed, and a complete examination was performed, in which macular flecks were observed, with yellow pigment arranged in oval distribution near their periphery. Due to the suspicion of Best\'s multifocal disease, genetic tests were performed. Multifocal vitelliform disease with the same features as those in Best\'s disease occurs most frequently in patients with a normal electro-oculogram (EOG), and a normal family history.
CONCLUSIONS: Best\'s multifocal disease must be suspected in case of multiple vitelliruptive lesions close to the posterior pole. Genetic testing is essential for its diagnosis.

Las mutaciones en un gran número de genes provocan degeneración de la retina y ceguera sin que exista actualmente cura alguna. En las últimas décadas, la terapia génica para enfermedades de la retina ha evolucionado y se ha convertido en un nuevo y prometedor paradigma terapéutico para estas enfermedades poco comunes. Este artículo refleja las ideas y los conceptos que parten de la ciencia básica hacia la aplicabilidad de la terapia génica en el ámbito clínico. Se describen los avances y las reflexiones actuales sobre la eficacia de los ensayos clínicos en la actualidad y se discuten los posibles obstáculos y soluciones de cara al futuro de la terapia génica para enfermedades de la retina.

METHODS: A 27-year-old woman with a history of nyctalopia and constriction of visual field of the right eye. The ophthalmological examination showed a visual field and electroretinogram that were compatible with unilateral retinitis pigmentosa (RP). After a one year follow-up, the unilateral condition remained.
CONCLUSIONS: Unilateral retinitis pigmentosa is a rare condition, with a frequency between 0.2%-5% of the RP. It mainly affects women and older age groups than bilateral RP. For a definitive diagnosis, it is necessary to have a funduscopy and electroretinogram (ERG) altered unilaterally, and exclude infectious, inflammatory, and vascular causes.