Alteration of vitreal retinoschisin level in human primary retinal detachment.

Alteration of Vitreal Retinoschisin Level in Human Primary Retinal Detachment Retinoschisin (RS1), the product of RS1 located on the X chromosome, is expressed mainly in retina.1 The 24-kDa RS1 encodes a highly conserved sequence motif termed the discoidin domain, which is a critical determinant of the structural and functional integrity of the retina.2 Mutations in RS1 that lead to either complete loss of RS1 expression or its accumulation as a nonfunctional misfolded form are the underlying causes of X-linked retinoschisis (XLRS).3 This disorder, seen exclusively in young males, is characterized by splitting, or schisis, affecting all retinal layers. The precise molecular mechanism by which RS1 functions is still undefined. During development, there is a wave of RS1 expression beginning at the retinal surface and spreading progressively in more distal retinal layers as they differentiate.4 In adult mice, RS1 is expressed in all retinal neurons except horizontal cells,4 with a predominance in photoreceptor inner segments and bipolar cells. In patients with XLRS, the retina is more prone to retinal detachment (RD) compared with the general population (10% vs 0.01%, respectively).5 These detachments are difficult to surgically reattach, making the postoperative outcome unfavorable.6,7 To assess the potential role of RS1 in retinal response to detachment, we analyzed RS1 levels in vitreous samples derived from patients’ eyes with or without RD.