NT5M, also known as DNT2, belongs to the 5'(3')-deoxyribonucleotidase family. It localizes to the mitochondrial matrix. This enzyme dephosphorylates the 5'- and 2'(3')-phosphates of uracil and thymine deoxyribonucleotides. The gene is located on chromosome 17 p11.2 in the critical region deleted in the Smith- Magenis syndrome (SMS), a genetic disease of unknown etiology.