Myoclonic dystonia

Myoclonic distonia or Myoclonus-dystonia syndrome is a rare syndrome having several subforms each traced to a different gene. The uniting feature is dystonia, but there are also rapid jerky movements resembling myoclonus.

Ethanol often ameliorates the symptoms very well, and so the syndrome is also called "Alcohol-responsive dystonia"; alcohol may be substituted by benzodiazepines that work through the same mechanism, such as clonazepam.

Myoclonus Dystonia is in most cases caused by loss-of-function-mutations in the epsilon sarcoglycan gene (SGCE). The disease is dominantly inherited: there is a 50% chance that a child will inherit the mutation if one parent has it. However, SGCE is an imprinted gene, and in fact only the paternal allele is expressed. That is, only children who inherit the mutation from the father will actually suffer from the disease. If the mutated allele is inherited from the mother, the child will most probably stay healthy.