Yes you can write off mortgage insurance premiums on your taxes as a tax deduction.
Mortgage insurance premiums on your taxes are considered itemized tax deductions and they are reported on line 13 of Schedule A, "Interest you paid.
However you can't claim the mortgage deduction if you claim the standard deduction as you must claim the mortgage insurance premium deduction on the Schedule A.
As long as you claim the mortgage insurance premium on schedule A of your tax returns you can claim the mortgage insurance premiums as a tax deduction.
I've done it myself after I asked my bank if I could do so and they said yes that you can do so.