U.S. Questions Fannie Mae Accounting  WASHINGTON (Reuters) - A U.S. government review into the  nation's No. 1 mortgage finance company, Fannie Mae &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=FNM.N target=/stocks/quickinfo/fullquote"&gt;FNM.N&lt;/A&gt;,  charges it with inappropriate accounting practices and called  into doubt past financial results, the company's board said on  Wednesday.