No. Here is from wikipedia:
http://en.wikipedia.org/wiki/BTX_%28form_factor%29
In the first months of production the ATX and BTX motherboards were so similar that moving a BTX motherboard to an ATX case was possible and vice-versa. This was possible because the first BTX motherboards were ATX motherboards turned upside down, except for the component location that really were BTX positioning.
Later the BTX form factor had a big change by turning it into a mirror image of the ATX standard. Since the new motherboard design, both standards are incompatible. Basically BTX motherboards are 'leftside-right' compared to ATX and not upside-down as before: i.e. they are mounted on the opposite side of the case. Some computer cases such as the...