Trisomy 21

What is Down syndrome?

Most individuals with Down syndrome, called trisomy 21, have an extra copy of chromosome 21 in the cells of the body. This extra genetic material causes changes in development of the embryo and fetus resulting in physical and developmental changes.

IQ typically ranges from mild to moderate intellectual disability. Health conditions can include low muscle tone, heart defects, intestinal issues and vision or hearing conditions. While the average life expectancy for a person with Down syndrome is 60 years, health conditions like those mentioned above may result in a shorter life expectancy.

Each person with Down syndrome is unique and the severity of the symptoms varies greatly among individuals. Outcomes for people with Down syndrome have improved significantly in the past 40 years with increased access to education, social supports, employment opportunities, and family support.

How common is Down syndrome?

Down syndrome occurs in about 1 in 800 live births. The condition is not related to race, nationality, religion or socioeconomic status. There is usually no family history of Down syndrome.

How is trisomy 21 (Down syndrome) treated?

There is no single, standard treatment for Down syndrome. Treatments are based on each individual's physical and intellectual needs as well as his or her personal strengths and limitations.

Individuals with Down syndrome may receive care from a team of health professionals, including physicians, special educators, speech therapists, occupational therapists, physical therapists, and social workers.