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Electrophysiological findings in a Danish family with Machado-Joseph disease
E Colding-Jørgensen1, S A Sørensen, L Hasholt
1Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark.
Abstract:
Machado-Joseph disease (MJD) is a neurodegenerative disorder with autosomal dominant inheritance, We have carried out electrophysiological studies in 8 individuals belonging to a Danish family with several affected members. Five had an expanded trinucleotide (CAG) repeat sequence in the MJD1 gene on chromosome 14 indicating MJD, while 3 unaffected individuals had normal repeat lengths. Three individuals with repeat expansion had clinical symptoms and signs of the Machado or "type III" phenotype, whereas 2 had slight symptoms and signs only, Electrophysiological evaluation included visual, somatosensory, and auditory brain stem evoked potentials, quantitative electromyography, and nerve conduction studies. In the patients with clinical MJD, evoked potential studies showed multimodal abnormalities, electromyography showed neurogenic changes, and nerve conduction studies showed signs of severe loss of motor and sensory nerve fibers. Of the 2 patients with slight symptoms and signs, 1 had evidence of peripheral and central affection, while the other had slight signs of a central affection. This study provides insight into the distribution and character of electrophysiological 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.
Insights
Machado-Joseph disease (MJD) is an inherited neurodegenerative disorder. Electrophysiological studies reveal widespread nerve damage in affected individuals, offering insights for disease understanding and treatment monitoring.
Area of Science:
- Neuroscience
- Genetics
- Neurology
Background:
- Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder.
- Genetic mutations, specifically expanded trinucleotide (CAG) repeats in the MJD1 gene, cause MJD.
- Electrophysiological studies are crucial for diagnosing and understanding neurological conditions.
Observation:
- This study examined 8 individuals from a Danish family with MJD.
- Five individuals carried the expanded CAG repeat, indicating MJD, while three unaffected individuals had normal repeat lengths.
- Clinical presentation varied, with some showing clear MJD phenotypes and others exhibiting only slight symptoms.
Findings:
- Electrophysiological evaluations included evoked potentials, electromyography, and nerve conduction studies.
- Patients with clinical MJD displayed multimodal evoked potential abnormalities, neurogenic electromyography changes, and severe nerve fiber loss.
- Individuals with milder symptoms showed peripheral and central nervous system involvement.
Implications:
- Electrophysiological abnormalities provide insights into MJD pathogenesis.
- These findings can aid in monitoring disease progression.
- This research may inform the development of potential treatments for Machado-Joseph disease.