Second Lafora Disease Gene Identified

Researchers have identified a second gene that causes Lafora disease (LD), the most severe form of teenage-onset epilepsy, and now explains the genetic basis for the disease in more than 90% of families with an afflicted child.

Lafora disease is a form of progressive myoclonus epilepsy beginning from age six to 19; characterized by generalized tonic-clonic seizures, resting and action myoclonus, ataxia, dementia, and classic EEG findings, including polyspike and wave discharges; basophilic cytoplasmic inclusion bodies present in portions of the brain, the liver, and skin, as well as the duct cells of the sweat glands. Death usually occurs within 10 years of onset. Lafora disease is passed by autosomal recessive inheritance.

In a study published in the September 2003 issue of Nature Genetics, investigators from the University of Toronto (Canada; www.utoronto.ca) reported the discovery of the NHLRC1 gene, which is the second gene found to cause Lafora disease. The other gene, EPM2A, was discovered five years ago.

"The newly discovered LD gene, named NHLRC1, produces a protein thought to be involved in marking other proteins for destruction in the cell. Our early data suggest that the EPM2A and NHLRC1 genes work together to safeguard neurons against accumulating too many carbohydrates. If either of the genes is missing, the result is epilepsy,” explained senior author Dr. Stephen Scherer, associate professor of molecular and medical genetics at the University of Toronto. "Importantly, we can now explain Lafora disease in 90% of families, and for the remaining 10%, we think there is a third yet-to-be-identified disease gene.”




Related Links:
University of Toronto