Jan 9 (Reuters) - Aegerion Pharmaceuticals Inc said on Thursday that it received a subpoena from the U.S. Department of Justice, requesting documents related to the marketing and sale of its cholesterol drug Juxtapid in the United States.

Aegerion shares fell more than 12 percent in extended trading.

Juxtapid was approved by U.S. health regulators in December 2012 to treat patients with homozygous familial hypercholesterolemia (HoFH), a rare genetic disease that impairs the function of the receptor responsible for removing LDL-C or "bad" cholesterol from the body.

The company said it intended to cooperate fully with the government investigation.

Chief Executive Mark Beer had received a warning letter from the U.S. Food and Drug Administration in November over statements that the regulator said misleadingly suggested Juxtapid was safe and effective in decreasing cardiovascular events and could be used as a stand alone therapy.

The FDA asked that the company respond with a plan to show it would not use promotional material containing the misleading statements and a strategy to adopt corrective measures in the marketing of the drug. ()

Juxtapid is the sole approved Aegerion product.

Aegerion on Thursday also reported preliminary net product sales of between $48 and $49 million, in line with its most recent guidance of between $45 and $50 million.

The Cambridge, Massachusetts-based company now expects net product sales of $190 million to $210 million in 2014. Analysts on average were expecting the company to post revenues of $204 million for the period, according to Thomson Reuters I/B/E/S.

Aegerion's shares were trading at $64.40 after the bell. They closed at $73.75 on the Nasdaq on Thursday.