Epigenetics may be involved in human diseases and health in many different ways. First, there are a small number of rare diseases that are considered epigenetic diseases, most of these involve mutations in genes for enzymes and proteins involved in making epigenetic modifications. Rett syndrome is one example in which people are born without a protein that is vital for the process of methylation that allows cells to shut off genes. Epigenetics may also play an active role in the development and the treatment of cancer, as the disease is characterized by ‘out of control cell division caused by mutations. Many researchers believe they can correct the behavior of these cells by altering the activity of these mutated genes. Drugs already exist on the market that does this, and the epigenetic drug market is expected to boom in the coming years driven mostly by new cancer drugs. There is emerging evidence that epigenetics may also play a vital role in treating diseases that don’t necessarily have etiologies rooted in gene regulation. Drugs that target gene activity as a treatment for Alzheimer’s disease, metabolic conditions, and autoimmune conditions may all soon be available.