We report a case of two siblings with progressive myoclonus epilepsy whose parents were not consanguineous. Their clinical symptoms were typical of Lafora disease (LD), but skin biopsies revealed no Lafora bodies. Whole-exome sequencing identified a recurrent homozygous frameshift variant in the NHLRC1 gene in both siblings. The genetic analysis was useful for the diagnosis of LD, as neither consanguinity nor Lafora bodies were found.