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Diseases

Genetic and Rare Diseases Information Center (GARD)

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Geniospasm


Other Names for this Disease

  • GSM 1
  • Hereditary chin tremor/myoclonus
  • Hereditary geniospasm
  • Trembling chin
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Overview

What is hereditary geniospasm?

How is hereditary geniospasm inherited?

How might hereditary geniospasm be treated?

What is hereditary geniospasm?

Hereditary geniospasm is a movement disorder that causes episodes of involuntary tremors of the chin and lower lip. The episodes may last anywhere from a few seconds to hours and may occur spontaneously or be brought on by stress. The episodes usually first appear in infancy or childhood and tend to lessen in frequency with age. Hereditary geniospasm is believed to be inherited in an autosomal dominant pattern. Although the exact gene(s) that cause the condition are unknown, it has been suggested that mutations in a gene on chromosome 9 may be responsible in some families.[1][2]
Last updated: 6/5/2013

How is hereditary geniospasm inherited?

Hereditary geniospasm is inherited in an autosomal dominant manner.[3] This means that having only one mutated copy of the causative gene in each body cell is sufficient to cause signs and symptoms of the condition. When an individual with an autosomal dominant condition has children, each child has a 50% (1 in 2) chance to inherit the mutated copy of the gene and also be affected. Because there is a 50% chance for each child, it is possible for all of the children of an affected individual to be affected, or likewise, for all of the children to be unaffected.
Last updated: 6/5/2013

How might hereditary geniospasm be treated?

Hereditary geniospasm, which may also be referred to as hereditary essential chin myoclonus, is generally considered a benign disorder although in some cases it can cause anxiety and social embarrassment.[4] Significant improvement with age has been reported.[3] Several drugs are used to treat myoclonus, such as benzodiazepines and anticonvulsants. However, individuals may not respond to a single medication and may experience significant side effects if a combination of drugs is used. It has also been suggested that botulinum toxin be considered as a primary treatment because it has been shown to be effective and well tolerated.[4]
Last updated: 6/5/2013

References
  1. Geniospasm 1. OMIM (Online Mendelian Inheritance in Man). June 30, 2004; http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=190100. Accessed 7/21/2009.
  2. Jarman PR, Wood NW, Davis MT, Davis PV, Bhatia KP, Marsden CD, Davis MB. Am. J. Hum. Genet. 1997; http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1715984&blobtype=pdf. Accessed 7/21/2009.
  3. Hereditary geniospasm. Orphanet. April 2009; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=53372. Accessed 6/5/2013.
  4. Devetag Chalaupka F, Bartholini F, Mandich G, Turro M. Two new families with hereditary essential chin myoclonus: clinical features, neurophysiological findings and treatment. Neurol Sci. June 2006; 27(2):97-103.


Other Names for this Disease
  • GSM 1
  • Hereditary chin tremor/myoclonus
  • Hereditary geniospasm
  • Trembling chin
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.