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Congenital familial hypertonia
Carl F DeLuca1, William J Cashore
1Women and Infants Hospital of Rhode Island, Rhode Island Hospital, Rhode Island, USA.
Insights
This congenital muscle rigidity disorder, likely hereditary, causes severe feeding and breathing issues. Intravenous diazepam offers temporary relief from continuous muscle activity.
Area of Science:
- Genetics and Neurology
- Congenital Neuromuscular Disorders
Background:
- Presents as a congenital, familial, and hereditary condition.
- Likely transmitted via a dominant gene, potentially on chromosome 5.
- Characterized by hypertonicity and rigidity of voluntary muscles from birth.
Purpose of the Study:
- To describe the clinical presentation and genetic basis of a rare congenital muscle rigidity disorder.
- To investigate the effects of diazepam on continuous electromyographic activity.
Main Methods:
- Clinical observation of congenital symptoms including feeding and respiratory difficulties.
- Electromyographic (EMG) recordings to assess muscle activity at rest.
- Administration of intravenous diazepam to evaluate its therapeutic effect.
Main Results:
- Patients exhibit feeding problems (dysphagia, laryngospasm) and respiratory issues (apneic episodes) due to muscle spasms.
- Sudden stimuli trigger prolonged rigidity, leading to characteristic "en bloc" falls.
- Continuous EMG activity at rest, without fasciculations, was observed and improved after diazepam administration.
Conclusions:
- The disorder is a hereditary neuromuscular condition with significant congenital manifestations.
- Diazepam shows potential for managing the continuous muscle activity characteristic of this disorder.
- Further research into the genetic and molecular mechanisms is warranted.
Abstract:
1. This complex of symptoms appears to be congenital, familial, and hereditary. It is apparently transmitted by a dominant gene, probably on chromosome 5. 2. Hypertonicity with rigidity of all voluntary muscles usually presents at birth. 3. Feeding problems are due to dysphagia or laryngospasm associated with aspiration and dyspnea. 4. Respiratory problems are characterized by apneic episodes due to muscle spasm. 5. Prolonged episodes of muscular rigidity secondary to sudden stimuli result in frequent falls, characteristically en bloc, like a statue. 6. Continuous electromyographic activity even at rest (with absence of fasciculations) improves after intravenous diazepam.