Do people with Down syndrome always have the physical characteristics?

Always is a big word. I have encountered some with very mild features & one that had the features of a dwarf & none recognizable as DS.Since every cell of their body has the same extra chromosome, certain organs/areas tend to have the same problems. Their facial features/hands/feet are similar.Their heart often has a defect,but not always the same one. They share similarities but there is variation within this group.