Rep. Darrell Issa (R-Calif.), chairman of the House Oversight and Government Reform Committee, wants a top Obama administration health official and one of the brains behind the Affordable Care Act to testify about alleged ‘deceptions’ with the law.

Issa on Thursday sent letters to Centers for Medicare and Medicaid Services (CMS) Administrator Marilyn Tavenner and MIT economist Jonathan Gruber asking them to testify at a hearing on Dec. 9.

Rep. Darrell Issa (R-Calif.) has called Jonathan Gruber, pictured here, to testify about Obamacare. (AP/Pablo Martinez Monsivais)

The requests came shortly after Republicans on the committee revealed that the administration had inflated the Obamacare enrollment statistics by including as many as 400,000 stand-alone dental plans in the official count — veering from the usual practice.

The letters also followed recent turmoil over years-old comments from Gruber, a key adviser during the drafting of the law, who said at a recorded event that the law’s architects used “tortured language” to keep parts of the measure from being scored as tax increases and added that “lack of transparency is a huge political advantage.”

Health and Human Services Secretary Sylvia Mathews Burwell on Thursday acknowledged an error with the enrollment numbers, saying that CMS, which falls under her department, made a “mistake” that is “unacceptable.” Gruber recently said that he regrets his comments, as Democrats and the White House tried to distance themselves from him.

None of those actions have sufficed for Issa, who says he still wants answers.

“From the outset, the health law has been the poster child for this administration’s broken transparency promises,” he said in a statement on Friday. “I expect Mr. Gruber and Administrator Tavenner to testify publicly next month about the arrogance and deceptions surrounding the passage and implementation of Obamacare.”

Attempts to reach Gruber at his MIT office on Friday were unsuccessful. CMS said in a statement that the agency plans to work with the committee on this request, noting that Issa asked for a response by Monday.