Did you opt for the Refund
Processing Service (also called pay-with-your-refund)? It gives you the option
to deduct your TurboTax fees from your federal tax refund.
Or You might have a refund
offset:
If so you will receive a notice
explaining the refund offset. The offset could have been from delinquent debt,
such as past-due child support, outstanding student loans, or unpaid state
income tax. The notice will reflect the
original refund amount, your offset amount, the agency receiving the payment,
and the address and telephone number of the agency.
https://ttlc.intuit.com/questions/1894477-why-is-my-federal-refund-less-than-i-expected