A case of late-onset dopa-responsive isolated dystonia secondary to a novel tyrosine hydroxylase gene variant

Utility of Clinical Exome Sequencing in Dystonia: A Single-Center Study From India

Objective

With the use of next-generation sequencing in clinical practice, several genetic etiologies of dystonia have been identified. This study aimed to ascertain the utility of clinical exome sequencing (CES) in dystonia and factors suggestive of a genetic etiology.

Methods

This study was a retrospective chart review of patients with dystonia who had undergone CES for the evaluation of dystonia.

Results

Forty-eight patients (35 males, 46 families) with dystonia were studied, with a mean age at onset of 16.0 ± 14.1 (1–58) years. A pathogenic/likely pathogenic variant was found in 20 patients (41.7%) among which 14 patients (29.2%) carried a novel variant. CES was more likely to detect a genetic diagnosis in patients with an early age at onset, i.e., ≤ 20 years.

Conclusion

CES is a useful tool in the diagnostic evaluation of dystonia, with a yield of close to 40%. Patients with an earlier age at onset have a higher likelihood of having dystonia due to a genetic cause than those with a later age at onset.