Abstract
Purpose: :
To develop a molecular genetic test to ‘early’ detect KC to be used in screening for refractive surgery and genetic counseling of family members of patients with KC.
Methods: :
We have previously reported the suppression of transcripts of prominent epithelial cell marker Aquaporin 5(AQP–5) a water channel protein in fresh KC corneal transplant buttons immersed in RNA–later(Invest Ophthalmol Vis Sci 2005:46:1230–1246) In order to confirm these findings and to try refine this as a test for the early detection of KC, we performed the following experiments. We submitted 8 corneal buttons( 4 KC and 4 pseudophakic bullous keratopathy) and 8 corneal scleral rims from the donor corneas at the time of transplant in a blind fashion to an independent laboratory for RT–PCR analysis using ESX an epithelial marker as a normal control. We also tested 6 PRK specimens( 8 mm diameter specimens of epithelium only) of patients with mild KC for AQP–5 and ESX
Results: :
RT–PCR detected AQP–5 and ESX in all pseudophakic bullous keratopathy specimens and all donor corneo–scleral rims. In the 4 KC buttons and in the 6 PRK specimens with mild KC, ESX was present but AQP–5 was absent in all specimens.
Conclusions: :
AQP–5 is suppressed in patients with mild clinically detectable KC. Future studies will focus on testing patients with ‘forme fruste’ KC to determine whether AQP–5 is a marker for subclinical disease. Supported by NEI 09052, the Skirball Program in Molecular Ophthalmology and the Eye Birth Defects Research Foundation, Inc
Keywords: keratoconus • gene screening • cornea: epithelium