Apple human interface vice-president Greg Christie, one of the key people involved in building the original iPhone, is leaving the company, according to a new report.

After his departure, all of Apple's software design will report to senior vice-president Jony Ive, who Christie reportedly had problems with.

Citing "sources briefed on the matter," 9to5Mac reported Christie — who currently leads software design for iOS — will leave Apple "soon." Ive became the head of human interface design in 2012 following the departure of iOS chief Scott Forstall, but Christie and his team still reported to senior vice-president of software engineering Craig Federighi. When Christie departs, all software designers will report to Ive, the report said.

Apple recently raised Christie's profile by having him grant interviews with the Wall Street Journal and NPR on the iPhone's creation, ostensibly as ammunition in its current legal battles with Samsung over patent infringement. That makes the timing of his departure curious, and lends support to the theory of a falling out with Ive.

Apple is expected to unveil new software for its mobile and desktop platforms, iOS 8 and OS X 10.10, at its Worldwide Developers Conference (WWDC) on June 2. The report said the new version of OS X would follow the aesthetic of iOS 7, elevating flat design in place of textures — something Christie was instrumental in implementing in earlier versions of iOS and OS X.

Apple commentator John Gruber at Daring Fireball called Christie's departure a "huge deal," adding that "Christie’s influence over the look and feel of OS X and (at least pre-7) iOS cannot be overstated. Say goodbye to Lucida Grande in OS X."

Apple did not immediately respond to a request for confirmation of Christie's departure.

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