Mutations in a Sibship with Multifocal Polymyoclonus.

Background: Advances in molecular genetic technologies have improved our understanding of genetic causes of rare neurological disorders with features of myoclonus.

Case Report: A family with two affected siblings, presenting with multifocal polymyoclonus and neurodevelopmental delay, was recruited for whole-exome sequencing following unyielding diagnostic neurometabolic investigations. Compound heterozygous mutations in , a gene previously associated with various epilepsy phenotypes and hearing loss, were identified in both siblings. The mutations included a missense change c.457G>A (p.Glu157Lys), and a novel frameshift mutation c.545del (p.Thr182Serfs*6).

Discussion: We propose that related diseases should be in the differential diagnosis for children with polymyoclonus.