Three siblings of a consanguineous parents with involuntary movements are reported. The mother had only a very slight neck tremor, without any other neurological abnormality, and the father had died. The 38-year-old son (Case 1) complained of involuntary movements at the age of 6. His involuntary movements were observed in the tongue, perioral region and upper and lower extremities: jerky movements with dystonic features. The 46-year-old elder brother (Case 2) experienced involuntary movements at the age of 18. Involuntary movements were observed in the upper extremities; he also had torticollis and tremulous movements in the neck, and jerky movements in the perioral region. They showed gait disturbance and dysarthria. The 35-year-old sister (Case 3) also experienced involuntary movements. When she was writing, her involuntary movements were obvious: dystonia and myoclonic jerks. Tremor in the neck was also seen. Their intelligence was below average. We concluded that this family had hereditary torsion dystonia, with myoclonus, and low intelligence. This condition may be associated with an autosomal recessive gene.