According to www.IRS.gov.(Publication 4808) A parent with a child with a disability is entitled to the EITC (Earned Income Tax Credit)AND the CTC (Child Tax Credit) even if they DON'T have to pay taxes, you must file a tax return and they give you the credit (worth hundreds of dollars) which turns into a refund check.
Plus as of 2009 through 2012, even if you save your whole refund for 12 months, no federal government agency can hold that money against you when giving you your benefits.

Also, if you want to file an itemized deduction (long form 1040), you would first add up all your receipts, (separating the medical receipts because, after you add them up you can only claim them if they amount to MORE than 7.5% of your adj.gross income), THEN if the total of your receipts adds up to more than your standard deduction use the long form. Here's this years standard deductions with one child:
Head of Household: $9,950
Married Filing Jointly: $12.750
Also it is my suggestion to those of you that have that much in deductions go to a professional tax preparer so that all the additional forms and attached schedules will be correct. I've been certified with H&R Block off and on for over 15 years. It's worth every dime to pay for a good tax return. Good luck.

In my state, the diagnosis itself is worth $100 write off. I may be crazy, but I think parents of disabled kids should be given much more write-offs than currently available,regardless of income. It's not like like therapies are free...

You would need Publication 503, for The Child and Dependent Care Credit (which also allows you to take day care, and also summer day camp off) for a another credit when you itemize your deductions.

in order to qualify for the EITC, if your'e married filing jointly, your AGI must be less than $40,545 with one qualifying child. I'm not sure how this will benefit us if our AGI is more than this.
I'm also curious if I can get credit for any daycare expenses for another child even though I stay at home.