What is the definition of Lafora Disease?
Lafora disease is an inherited, severe form of progressive myoclonus epilepsy. The condition most commonly begins with epileptic seizures in late childhood or adolescence. Other signs and symptoms include difficulty walking, muscle spasms (myoclonus) and dementia. Affected people also experience rapid cognitive deterioration that begins around the same time as the seizures. The condition is often fatal within 10 years of onset. Most cases are caused by changes (mutations) in either the EPM2A gene or the NHLRC1 gene and are inherited in an autosomal recessive manner. Treatment is based on the signs and symptoms present in each person.
What are the alternative names for Lafora Disease?
- Lafora body disorder
- Epilepsy progressive myoclonic 2
- Myoclonic epilepsy of Lafora
What are the causes for Lafora Disease?
Most cases of Lafora disease are caused by changes (mutations) in either the EPM2A gene or the NHLRC1 gene. These genes encode proteins that play a critical role in the survival of nerve cells (neurons) in the brain. Although the proteins are thought to have many functions in the body, one important role is to help regulate the production of a complex sugar called glycogen (an important source of stored energy in the body). Mutations in the EPM2A gene or the NHLRC1 gene interfere with the production of functional proteins, leading to the formation of Lafora bodies (clumps of abnormal glycogen that cannot be broken down and used for fuel) within cells. A build up of Lafora bodies appears to be especially toxic to the cells of the nervous system and leads to the signs and symptoms of Lafora disease.
What are the symptoms for Lafora Disease?
The signs and symptoms of Lafora disease generally appear during late childhood or adolescence. Prior to the onset of symptoms, affected children appear to have normal development although some may have isolated febrile or nonfebrile convulsions in infancy or early childhood.
The most common feature of Lafora disease is recurrent seizures. Several different types of seizures have been reported including generalized tonic-clonic seizures, occipital seizures (which can cause temporary blindness and visual hallucinations) and myoclonic seizures. These seizures are considered "progressive" because they generally become worse and more difficult to treat over time.
With the onset of seizures, people with Lafora disease often begin showing signs of cognitive decline. This may include behavioral changes, depression, confusion, ataxia (difficulty controlling muscles), dysarthria, and eventually, dementia. By the mid-twenties, most affected people lose the ability to perform the activities of daily living; have continuous myoclonus; and require tube feeding and comprehensive care.
What are the current treatments for Lafora Disease?
Unfortunately, there is currently no cure or way to slow the progression of Lafora disease. Treatment is based on the signs and symptoms present in each person. For example, certain medications may be recommended to manage generalized seizures. In the advanced stages of the condition, a gastrostomy tube may be placed for feeding. Drugs that are known to worsen myoclonus (i.e. phenytoin) should be avoided.
What is the outlook (prognosis) for Lafora Disease?
The long-term outlook (prognosis) for people with Lafora disease is unfortunately poor. There is currently no cure for the condition and it is considered progressive (symptoms worsen over time). By the mid-twenties, most affected people lose the ability to perform the activities of daily living; have continuous myoclonus; and require tube feeding and comprehensive care. On average, affected people survive approximately 10 years after the onset of symptoms.
Is Lafora Disease an inherited disorder?
Lafora disease is inherited in an autosomal recessive manner. This means that to be affected, a person must have a mutation in both copies of the responsible gene in each cell. The parents of an affected person usually each carry one mutated copy of the gene and are referred to as carriers. Carriers typically do not show signs or symptoms of the condition. When two carriers of an autosomal recessive condition have children, each child has a 25% (1 in 4) risk to have the condition, a 50% (1 in 2) risk to be a carrier like each of the parents, and a 25% chance to not have the condition and not be a carrier.