However, there are also important differences, which include: the occurrence of arachnodactyly in the Lgj, Lgj2J and Stri models [21]; sacral/tail kinks in the Lgj, Lgj2J, Stri and Npr3 null mice [21, 25]; and premature death in Lgj2J and Npr3 null mice [21, 25]. The gene discussed is NPR3; the disease is congenital contractural arachnodactyly.