 Pseudohypoparathyroidism type 1a PHP1a is a disorder that causes many endocrine and developmental problems. To date, medical treatment has focused primarily on maintenance of normal serum levels of calcium, phosphorous, and thyroid hormone. However, these therapeutic interventions do not address the problems of short stature, obesity, and subcutaneous ossifications, which for many are a source of considerable morbidity and personal distress. These patients require frequent medical care, blood tests, and medication adjustments. PHP1a is an inherited condition with an estimated prevalence in the United States of 1:15,000- 20,000, and the studies that we propose provide an opportunity to improve the quality of life in affected patients. We have found that growth hormone GH deficiency is common in these patients, and our data suggest that GH testing should be part of their routine standard of care. We are investigating whether GH treatment can increase final adult height. We are also investigating whether GH treatment can reduce weight and improve a variety of metabolic disturbances and overall health in both children and adults. 