A tax break that has long been untouchable could soon be in for some serious scrutiny.

Many home buyers deduct their mortgage interest when assessing their tax bill, a perk that has helped bolster the income of millions of families — and the broader housing market.

But as President Obama and Congress try to hash out a deal to reduce the budget deficit, the mortgage interest deduction will likely be part of the discussion.

Limits on a broad array of deductions could emerge in any budget deal. It is likely that any caps would be structured to aim at high-income households, and would diminish or end the mortgage tax break for many of those taxpayers.