A Japanese family with dystonia due to a pathogenic variant in SGCE

Dystonia (DYT) is a heterogeneous neurological disorder, and there are many types of DYT depending on the responsible genes. DYT11 is an autosomal dominant DYT caused by functional variants in the SGCE gene. We examined a Japanese patient with myoclonic dystonia. By using exome analysis, we identified a rare variant in the SGCE gene, NM_003919.3: c.304C > T [Arg102*], in this patient. Therefore, this patient has been molecularly diagnosed with DYT11. By Sanger sequencing, we confirmed that this variant was paternally inherited in this patient. By allele-specific PCR, we confirmed that the maternally inherited normal allele of SGCE was silenced, and only the paternally inherited variant allele was expressed in this patient. Despite the pathogenicity, identical variants have been recurrently reported in eight independent families from different ethnicities, suggesting recurrent mutations at this mutational hotspot in SGCE.