Progressive pseudobulbar paresis, early choreiform movements, and later rigidity: appearance in two sets of dizygotic twins in the same family.

In a family with two sets of dizygotic twins, three, possibly all four, siblings were affected by the same disorder. The parents were unrelated and the illness seemed limited to one generation. Onset was in the early to mid-20s with tics and choreiform movements, dysarthria, and dysphagia. Two twins had epilepsy. There was a marked dyscoordination of bulbar musculature reminiscent of pseudobulbar paresis. Involuntary movements were prominent during the first years, but then disappeared and were replaced by an akinetic-rigid parkinsonian appearance in the late stage. The intellect remained largely intact. Tendon reflexes were reduced. Varying degrees of peripheral nerve changes were seen. Two patients died after 22-24 years from causes indirectly related to the main illness. Marked degenerative changes were found in the caudate nucleus and putamen. Acanthocytes in significant numbers could not be detected in peripheral blood. Lipoproteinelectrophoresis was normal. Creatine kinase levels were moderately raised in one patient, normal in the others. Although certain clinical resemblances exist with neuroacanthocytosis, the exact nosologic status of the disorder has not been determined.