Autosomal recessive
Caused by changes in both copies of HPCA, which encodes hippocalcin, a protein involved in calcium homeostasis. Only a small number of families have been reported.
Signs and symptoms
Dystonia with onset from infancy to early adulthood, often starting in the limbs or neck and becoming generalized in most cases. Some people also have developmental delay or intellectual disability. Tremor was reported in all patients in one review (S3), and seizures can also occur.
What a diagnosis changes
Treatment is symptomatic. Common dystonia medicines often had little effect in reported cases, so physiotherapy and other supportive care are used. Both parents of an affected child are usually carriers, so each further child has a recurrence risk; genetic counselling and carrier testing of relatives are available.
Genes analysed
Includes 1 related subtype ↓Hide subtypes ↑
- torsion dystonia 2
