Mann-Whitney tests revealed men and women with SCD did not differ in education level (W = 414,105.0, p = 0.68) or number of APOE ε4 carriers (W = 4382.00, p = 0.53), but men were older (W = 5094.5, p = 0.03). This evidence concerns the gene APOE and Schnyder corneal dystrophy.