(Reuters:) Gap Inc (NYSE 🙂 lowered its quarterly sales forecast Thursday. It blamed execution issues at Old Navy Brand and “macroeconomic dynamic” which sent shares down 12% during extended trading.

Gap announced that Nancy Green, the Old Navy brand head, is leaving the company. Sonia Syngal, the Chief Executive Officer of the company, will continue to lead the team until another successor is hired.

Many clothing chains including Gap have had to struggle with growing demand.

Gap anticipates that its first-quarter sales will fall in the mid to middle teens percentage range, compared with previous guidance which was single-digit and low-single-digit annual declines.

Retailer Old Navy will be reporting its first quarter results May 26.