The prepubertal testicular tissues used (1st part of the study) and those which were further examined (2nd part of the study), were found to be highly heterogeneous with respect to the germ cell (DDX4+) and spermatogonial cell (PIWIL4+) quantities: The total DDX4+ cell counts varied between approximately 70 and 1050 cells/mm2 (Figure 6g), whereby the patient with SCD displayed the lowest DDX4+ germ cell count. Here, PIWIL4 is linked to Schnyder corneal dystrophy.