Primary torsion dystonia due to the Tor1A GAG deletion in an Irish family.

BACKGROUND:

Early, limb-onset primary torsion dystonia (PTD) is commonly due to a trinucleotide GAG deletion in the TOR1A (DYT1) gene on chromosome 9q34. The majority of carriers of this mutation conform to a characteristic phenotype that is similar in different ethnic populations.

AIM:

To describe the clinical features of affected members of a large Irish family with PTD due to the TOR1A deletion.

METHODS:

Fourteen consenting family members from three generations were examined according to a standardised protocol.

RESULTS:

Five affected individuals were identified. Two had a somewhat atypical phenotype with focal and segmental upper-limb dystonia without further progression.

CONCLUSION:

The authors describe the clinical features of PTD due to the TOR1A GAG deletion in an Irish family illustrating the presence of intrafamilial phenotypic variability.