Clinical Guidance

No clinically relevant genotype-phenotype correlations have been identified.

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"

Diagnostic Criteria

No consensus clinical diagnostic criteria for DYT-TOR1A have been published.

Suggestive Findings

DYT-TOR1A should be suspected in probands with the following clinical and supportive imaging findings and family history. Clinical findings

• Onset is in childhood or adolescence (median age: 9 years; interquartile range: 7-12 years).

• Dystonia usually begins in a leg (average age: 9 years) or an arm (average age: 15 years).

• Initiation or worsening of dystonic movements and postures often follows voluntary movements.

• Absence of:

• Other neurologic or systemic manifestations

• A history of a known cause of acquired dystonia (See .)

Imaging findings. Brain CT and routine MRI are normal.

Family history

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

Management Guidelines

No clinical practice guidelines for DYT-TOR1A have been published. In the absence of published guidelines, the following recommendations are based on the authors' personal experience managing individuals with this disorder. Evaluations Following Initial Diagnosis To establish the extent of disease and needs in an individual diagnosed with DYT-TOR1A, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended. Table 3. DYT-TOR1A: Recommended Evaluations Following Initial 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"

Surveillance Guidelines

To monitor existing manifestations, the individual's response to supportive care, and the emergence of new manifestations, the evaluations summarized in are recommended. Table 5. DYT-TOR1A: Recommended Surveillance

Source: GeneReviews — "DYT-TOR1A"