CODOMINANT INHERITANCE OF HYPEREKPLEXIA AND SPASTIC PARAPARESIS

In four generations of a family with autosomal dominant hyperekplexia (startle disease), untreated affected adult members had pes cavus and extensor plantar responses, as well as hyper-reflexia. Electroencephal ography during a startle, electromyography, nerve conduction velocitie s and somatosensory evoked potentials were normal. Genetic studies sho wed linkage to the CSF1R locus on chromosome 5q33-q35, which includes the glycine receptor. This either represents a variant of hyperekplexi a with spasticity or suggests that genes for hyperekplexia and a form of hereditary spastic paraparesis may be closely linked.