Down syndrome is a set of physical and mental traits caused by a gene problem that happens before birth. People with Down syndrome tend to have certain features, such as a flat face and a short neck. They also have some degree of intellectual disability. This varies from person to person. But in most cases, it is mild to moderate. Although having Down syndrome presents some challenges, most people with the condition can flourish and live healthy, happy, and productive lives. Most adults with Down syndrome function well in mainstream society. They often have regular jobs, have friends and romantic relationships, and participate in community activities. Follow the links below to find WebMD's comprehensive coverage about Down syndrome in adults, how to overcome obstacles, and much more.