P.053 Whole-genome sequencing identified a frameshift mutation at LMNB1 in a family with early-onset dystonia

Background: Dystonia is a hyperkinetic condition that produces abnormal movements or postures. Its diagnostic procedure is often challenging and time consuming. Genetic testing provides an effective approach for diagnosis, but currently only very few dystonia genes have been identified. We propose that studying early-onset forms of dystonia with the use of whole-genome sequencing (WGS) will improve the identification of dystonia-relevant genes and mutations. Methods: We performed deep WGS using the Illumina HiSeq X technology in a mother-proband pair with dystonia. The mother has generalized dystonia (age of onset: 15) and the proband has myoclonic dystonia (age of onset: 11). Results: No pathogenic mutation was identified in any of the known dystonia genes. However, we identified a rare heterozygous frameshift mutation (p.K342fs*7) at LMNB1 that was shared between the mother and the proband. Duplication of LMNB1 is known to cause Adult-onset Demyelinating Leukodystrophy. A heterozygous deletion of LMNB1 has been reported in a patient with microcephaly and global developmental disorder. Conclusions: Further characterization of phenotypes in the participants and their family members is needed to confirm the relationship between mutation in LMNB1 and dystonia. This work provides a proof-of-principle that novel disease-relevant genes can potentially be identified using the proposed approach.