Besides these similarities in appearance, those afflicted with Down's syndrome have weak and inflexible muscles and low stability in their joints. These conditions effect their development of movement. At the same time, they will have varying degrees of mental retardation and perhaps complications such as heart disease and low resistance to disease.
除了這些外表的共同特徵之外，唐氏症患者的肌肉張力低、關節穩定度差，影響動作發展，同時會有不同程度的智能不足，以及一些合併症，如心臟病、抵抗力差等等。