Bardet-Biedl syndrome with chorioretinal coloboma: a case series and review of literature.

INTRODUCTION

Bardet-Biedl Syndrome (BBS) is a ciliopathy causing developmental defects and progressive retinal dystrophy, whereas choroidal coloboma is a developmental defect causing structural deficiency in the posterior retina. Both are rarely reported together.

METHODS

Here, we describe the phenotype and genotype of three unrelated patients with co-occurrence of Bardet-Biedl Syndrome and chorioretinal coloboma and review the pertinent literature.

RESULTS

We describe three unrelated patients, with variable clinical features of Bardet Biedl syndrome. None had family history of BBS or coloboma. Each carried biallelic variants in , and gene, respectively. Two had unilateral chorioretinal coloboma, while one had bilateral chorioretinal coloboma.

DISCUSSION

Although there may be other explanatory factors yet to be revealed, our data suggests that chorioretinal coloboma may be associated with BBS. The Hedgehog (Hh) signaling pathway, an intercellular communicator for development of the eye, is dependent on the primary cilia and plays a crucial role in the closure of the optic fissure. Both disorders therefore involve disruption of primary cilia function which may explain their association.