Frequencies of CD45RA+ within CD4+ T cell subpopulations were significantly higher in the control patients relative to both SCD (40.31% (range 20.79-59.84) vs. 10.78% (range 2.34-28.6), p = 0.0005) and SCD/ON (40.31% (range 20.79-59.84) vs. 12.60% (range 2.37-25.02), p = 0.0001) patients. This evidence concerns the gene CD4 and Schnyder corneal dystrophy.