Lafora disease and founder effect in a small neotropical locality

The Lafora disease is an uncommon genetic condition. Four cases (two famili es) were detected in Zarcero, a small town in Costa Pica (population under 2000). They belonged to two separate consanguineous marriages but both fami lies had common ancestors. The diagnosis of Lafora disease was confirmed by liver biopsy in one of the patients. The ages of onset were 13, 14, 16 and 17 years. Patients died after four, nine, six and ftve years of severe pro gressive physical and mental deterioration, respectively. The gene for Lafo ra disease arrive to Zarcero from one of its founders. There are no other c ases reported from Costa Pica: this is an example of genetic drift, or more specifically, founder effect.