Over recent years, impressive advances in genetic/epigenetic technology have greatly improved the understanding of the pathogenesis of pediatric endocrine diseases due to hormone resistance and hypersensitivity. This book presents reviews of thyroid hormone and thyroid hormone receptor resistance, and genetics and epigenetics of parathyroid hormone resistance. Abnormalities of the pituitary-gonadal axis affecting puberty as well as androgen receptor are covered. Novel insights into the diseases affecting ACTH, glucocorticoid and aldosterone receptors are discussed. Further chapters address new aspects of the physiology of the GH and IGF-1 axis as well as the diseases related to GH-IGF-1 receptor and post-receptor signaling defects. A key chapter on metabolic insights into insulin resistance is also included. Covering clinical and genetic aspects of hormone resistance and hypersensitivity, this book will be a useful tool in the hands of scientists, physicians and other healthcare professionals who wish to be up to date with novel research findings in this area.