You can claim the income tax exemption provided your name is also included in the application for a loan to the concerned bank.
When we apply for a loan what we have to do is we have to mention the name of the owner of the house as number one applicant. Then your name as the applicant two. Then they will take your signature and other details. In the loan sanction letter also they will mention both names. Anyone of you can claim the income tax exemption for that money as per IT rules. If your name is not there you can't claim the exemption. Then you can claim only HRA exemption as per the IT rules by showing that you are on rent in that house and your mother can give you a rent receipt.
If already you have taken down without your name, you can ask the lown sanctioning authority to include you name as applicant two. If they say there is no provision you can apply for transfer of the loan to another organisation wherein you can include your name also as an applicant for a loan.