Bootcamp and Macbook Pro and TrueCrypt
The first partition on an Apple Disk Utility drive is a 200MB EFI System Partition. OS X 10.8 and older do not need it for booting, but it is used for staging firmware updates. If it's removed, firmware updates won't be possible. Depending on exactly what TrueCrypt wants, you could resize the EFI System Partition, as 200MB isn't really required, by changing the start sector and then reformatting the EFI System partition (as FAT32).