Torsin 1A is a protein mutated in torsion dystonia type 1, a hereditary neurological disorder of early onset and variable clinical picture. The basic cellular function of torsin 1A, a polypeptide localized predominantly in the endoplasmic reticulum and nuclear envelope, remains unknown, although the protein is suspected of being involved in many different cellular processes, including regulating a proper structure and function of nuclear envelope, contributing to the synaptic vesicular trafficking, or assisting in proper folding of misfolded proteins. This review summarizes the current state of knowledge regarding the potential functions of torsin 1A in the context of hypothetical pathomechanisms responsible for torsion dystonia type 1.