Down’s syndrome

Abstract

Down’s syndrome is caused by trisomy of chromosome 21; it is one of the best known chromosomal disorders in humans. It has effects on most body systems, giving rise to a variety of characteristic clinical features including intellectual impairment, short stature, flat face, flat nasal bridge, prominent epicanthic folds, up slanting palpebral fissures and protruding tongue. Down’s syndrome is also associated with an increased risk of other medical conditions. All patients with Down’s syndrome have a degree of intellectual impairment ranging from mild to severe. This article considers the epidemiology, genetics, associated risks, antenatal screening and potential ethico-legal issues relating to the disorder before discussing clinical features, complications and monitoring requirements. Finally, Down’s syndrome management, prognosis, and future diagnostic tests are outlined.