Booker T. McNeill appeals the decision of the Court of Appeals for Veterans Claims, which affirmed the Board of Veterans’ Appeals’ decision denying his claim for service connection of post-traumatic stress disorder (“PTSD”). McNeill v. Nicholson, No. 05-1413, — Vet.App. - (Vet.App. Dec. 7, 2006). Because we do not have authority to review “a challenge to a law or regulation as applied to the facts of a particular case” absent a constitutional issue, 38 U.S.C. § 7292(d)(2), we dismiss his appeal.