Summary
The fundamental question for the field of Down Syndrome (DS) basic research is how an extra copy of human chromosome 21 (HSA21) translates into the organ-specific defects observed in the DS population. Control of when cells differentiate from progenitor to differentiated cell is important for normal organ formation. We will test the hypothesis that heart defects in DS are caused by failure of a Hedgehog signaling-dependent differentiation timing switch.