Definition The porphyrias, which are a group of disorders that arise from disturbances in heme synthesis, are characterized by the accumulation of porphyrins or their precursors on the heme biosynthetic pathway. Most porphyrias are genetic and heritable, except for the…
Definition Homocysteine, which is a nonprotein amino acid, is a key metabolic branch point metabolite between the trans-sulfuration and remethylation pathways of methionine metabolism. The many conditions associated with high homocysteine levels encompass a wide range of clinical manifestations. The…
The lysosomal storage diseases encompass a group of more than 70 different inherited disorders, all sharing a defect in lysosomal function. Lysosomes are acidic, membrane-bound organelles that are located in the cytoplasm and contain enzymes that degrade macromolecules. Lysosomal storage…
Definition Glycogen storage diseases are a group of disorders resulting from inherited defects in the biochemical pathways of glycogen metabolism. Based on organ involvement, glycogen storage diseases are broadly categorized into two groups: hepatic glycogen storage diseases and muscle glycogen…
Disorders of lipid metabolism are an increasingly common consequence of modern industrial lifestyles. With increasing prosperity, the spread of Western-style diets and sedentary habits is resulting in dramatic rises in obesity in countries around the world. Poor lifestyle habits coupled…
Overview Definition The definition of inborn errors of metabolism includes not only enzyme deficiencies but also any condition in which perturbation of a biochemical pathway is intrinsic to the pathobiology of the disorder. Inborn errors of metabolism can be classified…
Melanoma Epidemiology The incidence of melanoma continues to rise rapidly worldwide, but mortality rates are declining. Each year in the United States, nearly 100,000 new cases of invasive melanoma are detected, and approximately 7000 patients die from melanoma. Melanoma is…
Bone Tumors Primary bone tumors include osteosarcomas, chondrosarcomas, and Ewing sarcoma. These rare tumors, which arise from the normal cellular components of bone and can potentially metastasize, have an incidence of 1.8 new cases per 100,000 population per year and…
Epidemiology Prostate cancer is the most common nonskin cancer that affects U.S. men, with approximately 270,000 new cases diagnosed annually and approximately 35,000 deaths each year. Worldwide, approximately 1.4 million cases of prostate cancer are diagnosed annually and lead to…
Epidemiology Testicular cancer has an annual incidence of about 8700 cases per year in the United States and accounts for only 1% of all male malignancies. Nevertheless, it is the most common carcinoma in men ages 15 to 35 years.…