dgfashdgfjsdhf Knoblochs syndrome: a new genotype and phenotype reporting conservative management of presumed retinal detachment

C.K. Patel, Edward Hughes, Susan Downes

Abstract
Abstract
Abstract

We report 3 children referred to the paediatric retinal surgery service in Oxford in whom a unifying genetic diagnosis for retinal dystrophy was made possible by deep ocular phenotyping under anaesthetic. Novel aspects of the phenotype included the presence of retinoschisis with an outer leaf break, chorioretinal lesions and beaded anterior vitreous opacities. New mutations for Knobloch's syndrome are reported. The natural history through to adulthood is presented in one case.












Introduction

When retinal detachment is suspected in children clinical assessment with or without an anaesthetic aims to determine if its is rhegmatogenous, exudative, tractional or due to combined mechanisms. The differential diagnosis of rhegmatogenous retinal detachment is trauma, previous intraocular surgery, and collagenopathies such as Sticklers syndrome.  Once these are excluded there are rare syndromes that could be considered. We report two such cases and a third case who was a brother of one of the index cases where deep ocular phenotyping in the operating room led us to a clinical diagnosis of Knobloch's syndrome. We present novel aspects of the phenotype and genotype adding to the literature on this rare entity. Our cases highlight surgical dilemmas and suggest that conservative management is a reasonable option to pursue. 


Case presentations

Case 1

A 7 year old boy with infantile nystagmus, myopia, low vision(6/60) secondary to retinal dystrophy was referred for a specialist opinion with regard to an asymptomatic area of retinal elevation in the left eye in the supero-temporal quadrant(Figure 1). 

A year previously he had lost vision in the right eye from a total retinal detachment with a horseshoe tear in the upper temporal quadrant. He underwent a cryo-buckle surgery using a segmental circumferential silicone tyre(277) explant. His retina re-detached 4 weeks later requiring buckle exchange for a segmental silicone sponge(506). Two months later he developed aggressive proliferative vitreoretinopathy resulting in recurrence of retinal detachment requiring vitrectomy, encirclement and silicone oil tamponade . When cataract surgery was performed 6 months later, there was recurrent inferior retinal detachment requiring retinectomy and further oil tamponade. Eventually oil was removed and the eye became pthisical and blind requiring evisceration.