Exploring Knobloch syndrome: A case series of two Indian families and a review of literature

Abstract

This case series describes the clinical features and genetic testing results of four patients from two families affected by Knobloch syndrome (KS). KS is an autosomal recessive collagenopathy characterized by vitreoretinal degeneration, high myopia, retinal detachment, and occipital encephalocele. In addition, a myriad of other ophthalmic and systemic features may be present in the affected individuals. Mutations in the COL18A1 gene are primarily implicated in the pathogenesis of the disease. The phenotypical differences seen in our genetically-proven patients show the clinical heterogeneity of this condition. Diagnosis of KS type-1 was confirmed by genetic analysis in all affected patients. Surgical intervention was done to salvage vision in three patients. This case series highlights the importance of meticulous clinical examination and diagnosis of this rare condition. Genetic counseling and testing are important for suspected patients and for guiding patients on the visual prognosis of the disease.