ELECTROPHYSIOLOGICAL FINDINGS IN A DANISH FAMILY WITH MACHADO-JOSEPH DISEASE

Machado-Joseph disease (MJD) is a neurodegenerative disorder with auto somal dominant inheritance. We have carried out electrophysiological s tudies in 8 individuals belonging to a Danish family with several affe cted members. Five had an expanded trinucleotide (GAG) repeat sequence in the MJD1 gene on chromosome 14 indicating MJD, while 3 unaffected individuals had normal repeat lengths, Three individuals with repeat e xpansion had clinical symptoms and signs of the Machado or ''type III' ' phenotype, whereas 2 had slight symptoms and signs only, Electrophys iological evaluation included visual, somatosensory, and auditory brai n stem evoked potentials, quantitative electromyography, and nerve con duction studies. In the patients with clinical MJD, evoked potential s tudies showed multimodal abnormalities, electromyography showed neurog enic changes, and nerve conduction studies showed signs of severe loss of motor and sensory nerve fibers, Of the 2 patients with slight symp toms and signs, 1 had evidence of peripheral and central affection, wh ile the other had slight signs of a central affection. This study prov ides insight into the distribution and character of electrophysiologic al abnormalities in MJD of putative importance for an understanding of the pathogenesis of the disease, and for monitoring disease progress, or the outcome of a possible treatment. (C) 1996 John Wiley & Sons, I nc.