A Jefferson County sheriff's deputy died Monday of injuries sustained in an off-duty ATV wreck.   Brad Perry, 42, of Adger, was a 12-year veteran of the office.   Perry was injured Dec. 3, when the ATV he was riding with another off-duty deputy hit a hole and overturned, causing Perry to land on his head.   He was remembered as a dedicated lawman, by those who knew him.  "He not only came through the ranks  to become deputy sheriff in the Youth Services division, which is very sensitive," Sheriff Mike Hale said.    "That just ... exemplifies how Deputy Perry conducted his life, he cared about the citizens that he served."