Familial spasmodic dysphonia with low arylsulphatase A (ASA) level.

Two familial cases of late onset spasmodic dysphonia and low Arylsulphatase A (ASA) are reported. In one case spasmodic dysphonia was associated with negative head tremor and orthostatic tremor, both displayed postural tremor of the upper extremities. A familial predisposition for both focal dystonia and metabolic lysosomal impairment is suggested by similar observations.