üleliigsest kromosoom 21‑st (kahe asemel kolm) põhjustatud arenguhäire, millele on iseloomulikud tüüpilised näojooned, lühikesed sõrmed, liigeste lõtvus ja vaimne alaareng, a congenital condition characterized especially by developmental delays, usually mild to moderate impairment in cognitive functioning, short stature, upward slanting eyes, a flattened nasal bridge, broad hands with short fingers, decreased muscle tone, and by trisomy of the human chromosome numbered 21, genetic disorder, caused by the presence of an extra copy of chromosome 21 in a baby's cells, that affects a baby's normal physical development when it is still in the womb and causes mild to moderate learning difficulties