Seizures are only an occasional event in the course of most inherited diseases. They may be the predominant symptom, however, in some diseases. These include:
Generally, inherited disease onset in infancy is associated with a greater frequency of seizures than is the appearance of such a disease in juvenile or adult life.
The seizure pattern in infancy generally is mixed, consisting of atypical absence, atonic, and myoclonic phenomena, but generalized seizures with prolonged postictal lethargy also occur.
The mitochondrial encephalopathies are associated with myoclonic jerking. Focal twitching occurs in MELAS (mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes).
Reviewed and revised May 2004 by Steven C. Schachter, MD, epilepsy.com Editorial Board.
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