'North Sea' progressive myoclonus epilepsy: phenotype of subjects with GOSR2 mutation

We previously identified a homozygous mutation in the Golgi SNAP receptor complex 2 gene (GOSR2) in six patients with progressive myoclonus epilepsy. To define the syndrome better we analysed the clinical and electrophysiological phenotype in 12 patients with GOSR2 mutations, including six new unrelated subjects. Clinical presentation was remarkably similar with early onset ataxia (average 2 years of age), followed by myoclonic seizures at the average age of 6.5 years. Patients developed multiple seizure types, including generalized tonic clonic seizures, absence seizures and drop attacks. All patients developed scoliosis by adolescence, making this an important diagnostic clue. Additional skeletal deformities were present, including pes cavus in four patients and syndactyly in two patients. All patients had elevated serum creatine kinase levels (median 734 IU) in the context of normal muscle biopsies. Electroencephalography revealed pronounced generalized spike and wave discharges with a posterior predominance and photosensitivity in all patients, with focal EEG features seen in seven patients. The disease course showed a relentless decline; patients uniformly became wheelchair bound (mean age 13 years) and four had died during their third or early fourth decade. All 12 cases had the same variant (c.430G>T, G144W) and haplotype analyses confirmed a founder effect. The cases all came from countries bounding the North Sea, extending to the coastal region of Northern Norway. ‘North Sea’ progressive myoclonus epilepsy has a homogeneous clinical presentation and relentless disease course allowing ready identification from the other progressive myoclonus epilepsies.

Individual geographic mobility in a Viking-Age emporium—Burial practices and strontium isotope analyses of Ribe’s earliest inhabitants

Individual geographic mobility is a key social dynamic of early Viking-Age urbanization in Scandinavia. We present the first comprehensive geographic mobility study of Scandinavia’s earliest emporium, Ribe, which emerged around AD 700 in the North Sea region of Denmark. This article presents the results of strontium isotope analyses of 21 individuals buried at Ribe, combined with an in-depth study of the varied cultural affinities reflected by the burial practices. In order to investigate geographic mobility in early life/childhood, we sampled multiple teeth and/or petrous bone of individuals, which yielded a total of 43 strontium isotope analyses. Most individuals yielded strontium isotope values that fell within a relatively narrow range, between 87Sr/86Sr = 0.709 to 0.711. Only two individuals yielded values >87Sr/86Sr = 0.711. This suggests that most of these individuals had local origins but some had cultural affinities beyond present-day Denmark. Our results raise new questions concerning our understanding of the social and cultural dynamics behind the urbanization of Scandinavia