Werner syndrome with refractory cystoid macular edema and immunohistochemical analysis of WRN proteins in human retinas

BACKGROUND To present our findings in a case of Werner syndrome with refractory cystoid macular edema (CME) and to determine the expression and the distribution of WRN proteins in human retinas. CASE PRESENTATION A 35-year-old man with Werner syndrome who developed CME after YAG laser treatment was studied. Optical coherence tomographic (OCT) scans were used to examine the CME in the right eye. The patient received topical eye drops (0.1% bromfenac sodium hydrate twice daily and 1% dorzolamide hydrochloride thrice daily), sub-Tenon triamcinolone injection thrice, intravitreal bevacizumab injection twice, and pars plana vitrectomy of the right eye. Genetic analyses were performed to diagnose the disease. To examine the expression and distribution of WRN proteins in the retinas, immunohistochemistry for WRN proteins was performed in human retinas. The CME in the right eye was not improved by any of the treatments. During the follow-up period, CME developed in the left eye. Genetic analyses detected compound heterozygosity, Mut4 and Mut11, in the WRN gene and the individual was diagnosed with Werner syndrome. Immunohistochemical analysis of WRN proteins expression in human retinas showed that WRN proteins were expressed in the parts of the Müller cells in the inner nuclear layer and outer nuclear layer. CONCLUSION Patients with Werner syndrome can develop severe CME after laser treatment. A pathological link may exist between mutations in the WRN gene and the development of CME in patients with Werner syndrome.