ISLR2 and exfoliation syndrome: ISLR2 and STRA6 are both significantly downregulated in tissues of XFS patients together with other key components of the STRA6 receptor-driven Retinoic acid (RA) signaling pathway, and that siRNA-mediated downregulation of RA signaling induces upregulation of LOXL1 and XFS-associated matrix genes in XFS-relevant cell types [29].