The spectrum of Jansky-Bielschowsky disease.

A series of five patients with a variant type of Jansky-Bielschowsky disease is presented. The disease initiated between four and a half and seven years with mental and slight motor symptoms. The additional neurological symptoms and signs, i.e. visual failure, retinal degeneration, ataxia, myclonia and epilepsy developed in all children before the age of ten years. The present series differs from our previous series of 16 cases especially in regard of neurophysiological findings (photic spikes, high visual evoked potential, VEP and high somatosensory evoked potential, SEP). VEP became abnormally high between 8.0 and 9.5 years instead of being an early finding as in the previous series. Photic spikes appeared also later in the present series. Electromicroscopic investigation revealed cytosomes with fingerprint profiles (FP) in the autonomic ganglion cells and cytosomes with both FP and curvilinear (CP) profiles in many extraneural cells including smooth muscle, Schwann cells, capillary endothelium and macrophages. In the light of our 21 Finnish patients and the literature, the spectrum of Jansky-Bielschowsky disease seems to be much wider than previously assumed. The diagnosis should be based on clinical, ophthalmological, neurophysiological and ultrastructural findings. Repeated neurophysiological studies may be necessary.