The discovery is reported in the October issue of the prestigious scientific journal Nature Genetics.
Death usually occurs within a decade of the first symptoms.
While Lafora disease is rare in Canada, it is more common in Mediterranean countries and in Turkey, India and Iran. Fifty years of investigation led biochemists to suspect that LD was caused by problems with carbohydrate metabolism in the brain. Beyond this, however, the fundamental defect triggering the malfunction was unknown. The LD gene produces a signalling protein which is thought to be involved in the brain's breakdown of carbohydrates. The defective gene interferes with this process, leading to the accumulation of abnomal sugar molecules which likely lead to the destruction of the brain's nerve cells.