Diseases of mineral metabolism such as familial multiple endocrine neoplasia type 1 (FMEN1), familial hypocaliuric hypercalcemia (FHH), familial hyperparathyroidism (FH), and pseudohypoparathyroidism (PHP) are known as hereditary abnormalities. Meaning these conditions are passed from parents to their children through genes. These specific conditions result in abnormal levels of calcium in the blood. This study was designed to help researchers understand more about the genes that are responsible for these disorders. By learning more about the genetic process involved in hereditary abnormalities, new tests and treatments can be developed. Subjects for this study will be members of families that have had relatives diagnosed with a disease of mineral metabolism. Participants will be asked to give blood samples for DNA extraction. DNA is the part of cells that carries genetic information. The DNA will be analyzed and the results given to the subjects. Genetic counseling will be provided to subjects to aid in interpreting their results.

Patients whose parathyroid activity is elevated above normal are referred to as having hyperparathyroidism. This study will help researchers better understand the causes of hyperthyroidism and to evaluate and improve methods for diagnosis and treatment. In this study, patients diagnosed with or suspected of having hyperparathyroidism will be selected to participate. In addition, patients with related conditions such as parathyroid tumors, will also be selected. Subjects will be asked to provide blood and urine for testing to confirm their condition. They will then be surgically treated by removal of the parathyroid gland(s) (parathyroidectomy). Subjects with parathyroid tumors will undergo several diagnostic tests to determine the exact location of the tumor as well as the tumor's activity. The tests may include; ultrasounds, nuclear scanning, CT scans, MRI, and specialized blood testing. Sometimes parathyroidectomy leads to hypoparathyroidism. Options for treating the patients after the surgical procedure will also be addressed. Calcium and Vitamin D supplements are typically the mainstay of post parathyroidectomy therapy. Other potential treatments include transplanting the parathyroid gland(s) to other areas of the body.

Patients with confirmed or suspected conditions with a resistance to vitamin D or parathyroid hormone (PTH) will be admitted for diagnosis and treatment, and inclusion in other studies pertaining to similar conditions. This study will provide information about problems relating to calcium in the blood, urine, and bones. Patients in this study will undergo a general evaluation / check-up to give researchers an idea of each person's condition or disease. Patients will receive treatment based on their diagnosis and asked to provide specimen samples for further research studies.