 Menkes disease and occipital horn syndrome are two forms of copper deficiency that must be diagnosed and treated very early in life to prevent serious developmental problems. However, these and other forms of copper deficiency are not very well understood, and further research is needed to determine whether certain treatments are useful in treating copper deficiency. One such treatment is copper histidine, a copper replacement that can be injected directly into the body to avoid absorption through the gastrointestinal tract. This study will investigate the effectiveness, side effects, and dosage of copper histidine treatment for patients with copper deficiency. It will also collect medical history information from patients to allow researchers to study possible genetic and nongenetic origins of copper deficiency. 