Clinical Guidance

DYT1-TOR1A is an early-onset isolated dystonia with a median age of onset of nine years (interquartile range: 7-12 years); approximately 5% of individuals have onset after age 30 years . Onset is typically in an arm or a leg; however, when dystonia becomes generalized, axial and cervical involvement are common. Craniofacial or laryngeal involvement is uncommon. Presentation. Onset is usually in a leg (average age: 9 years) or an arm (average age: 15 years). Initially, dystonia is apparent with specific actions such as a change in gait (foot inversion or eversion, abnormal flexion of the knee or hip) or writer's cramp (dystonia of the upper extremity that is task specific to writing caused by tightening and/or posturing of the upper extremity).

Source: GeneReviews — "DYT-TOR1A"

Penetrance

The penetrance of the common

TOR1A deletion is approximately 30% . Thus, on average, 30% of individuals who inherit this variant will develop DYT-TOR1A and 70% will not.

Source: GeneReviews — "DYT-TOR1A"

Differential Diagnosis

DYT-TOR1A is estimated to account for approximately 16%-53% of early-onset dystonia in individuals who are not of Jewish ancestry and approximately 80%-90% of early-onset dystonia in the Ashkenazi Jewish population . In broader cohort studies involving individuals with various subtypes of isolated dystonia, DYT-TOR1A accounts for a low percentage of dystonia because isolated adult-onset focal dystonia (e.g., cervical dystonia) is far more common than early-onset isolated dystonia [, , , , , ]. Genetic disorders that may present with early-onset isolated dystonia in a limb and are in the differential diagnosis of DYT-TOR1A are listed in . Table 2. DYT-TOR1A: Differential Diagnosis

Source: GeneReviews — "DYT-TOR1A"

Clinical Guidance

Unless medically necessary, avoid immobilization with bracing or casting of the parts of the body affected by dystonia, which can worsen the dystonia.

Source: GeneReviews — "DYT-TOR1A"

Therapies Under Investigation

Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for access to information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.

Source: GeneReviews — "DYT-TOR1A"