Home What is a rare diseasE? achieving a diagnosis about the council Supporting people with rare diseases and their families. Learn more In the U.S., a rare disease is defined as a condition that affects fewer than 200,000 people. There are estimated to be 7,000 rare diseases. 30 million Americans are estimated to be living with a rare disease. This figure is equivalent to one in 10 people in the U.S. In Alabama, 400,000 people are living with a rare disease. This figure is equivalent to 8.2%of the state’s population More than 90% of rare diseases do not yet have a treatment approved by the FDA One in 33 babies in the U.S. is born with birth defects, which include rare diseases The Alabama Newborn Screening program identifies on average 150 to 200 babies with a metabolic, endocrine, hematological or other congenital disorder.