LEFTY2 and hyperinsulinemic hypoglycemia, familial, 4: Finally, several germ cell-specific genes including Boule-like RNA-binding protein (Boll), HORMA domain containing 1 (Hormad1), and Left-right determination factor 2 (Lefty2) were unchanged in mutant testes (Fig. 3C,D), indicating that changes in germ cell related genes (piRNA pathway components or Nanos genes) are not the result of general germ cell deficiency.