It is not specific to congenital disorders such as Down syndrome.The American Association on Mental Retardation changed its name to the American Association on Intellectual and Developmental Disabilities (AAIDD) in 2007, and soon thereafter changed the names of its scholarly journals to reflect the term "intellectual disability". In 2010, the AAIDD released its 11th edition of its terminology and classification manual, which also used the term intellectual disability. United Kingdom
In the UK, mental handicap had become the common medical term, replacing mental subnormality in Scotland and mental deficiency in England and Wales, until Stephen Dorrell, Secretary of State for Health for the United Kingdom from 1995 to 1997, changed the NHSs designation to learning disability. The new term is not yet widely understood, and is often taken to refer to problems affecting schoolwork (the American usage), which are known in the UK as "learning difficulties". British social workers may use "learning difficulty" to refer to both people with intellectual disability and those with conditions such as dyslexia.
People with the condition usually present with a painless swelling in the area of the clavicles at 2–3 years of age. Common features are:

Clavicles (collarbones) can be partly missing leaving only the medial part of the bone. In 10% of cases, they are completely missing. If the collarbones are completely missing or reduced to small vestiges, this allows hypermobility of the shoulders including ability to touch the shoulders together in front of the chest. The defect is bilateral 80% of the time. Partial collarbones may cause nerve damage symptoms and therefore have to be removed by surgery. The mandible is prognathic due to hypoplasia of maxilla (micrognathism) and other facial bones. A soft spot or larger soft area in the top of the head where the fontanelle failed to close, or the fontanelle closes late. Bones and joints are underdeveloped. People are shorter and their frames are smaller than their siblings who do not have the condition. The permanent teeth include supernumerary teeth. Unless these supernumeraries are removed they will crowd the adult teeth in what already may be an underdeveloped jaw. If so, the supernumeraries will probably need to be removed to make space for the adult teeth. Up to 13 supernumerary teeth have been observed. Teeth may also be displaced. Cementum formation may be deficient. Failure of eruption of permanent teeth. Bossing (bulging) of the forehead. Open skull sutures, large fontanelles. Hypertelorism. Delayed ossification of bones forming symphysis pubis, producing a widened symphysis. Coxa vara can occur, limiting abduction and causing Trendelenburg gait.