Primordial has been defined as belonging to or being characteristic of the earliest stages of development of an organism. Therefore, Primordial Dwarfism is a class of disorders where growth delay occurs at the earliest stages of development. Unlike some of the other forms of dwarfism where newborn infants can have average lengths, children with Primordial Dwarfism have intrauterine growth retardation (IUGR) and are born smaller than average. We will limit our discussion to one specific kind of primordial dwarfism here: microcephalic primordial dwarfism type II (MOPDII). Most of the information below can be examined in more detail in Bober and Jackson (1).