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Recognizing acquired demyelinating syndromes and multiple sclerosis is important to commence early treatment. The objective of this study was to describe the incidence of acquired demyelinating syndromes and multiple sclerosis among the entire Icelandic pediatric population according to recently promoted criteria.The study included all children in Iceland (18 years) with acquired demyelinating syndromes and multiple sclerosis from 1990 to 2009 with a minimum of 5-year follow-up. Clinical data were gathered and radiological images reviewed. The cohort included all patients with acquired demyelinating syndromes and multiple sclerosis in the Icelandic pediatric population.Eighteen patients with acquired demyelinating syndromes and multiple sclerosis were included, the total annual incidence being 1.15/100,000 (acquired demyelinating syndromes 1.02 and multiple sclerosis 0.45/100,000). The median age at diagnosis was 14.25 years (range 1.25-17.5 years). Thirteen patients were initially diagnosed with clinically isolated syndrome, two had acute disseminated encephalomyelitis, two had multiple sclerosis, and one had neuromyelitis optica. Seven children were diagnosed with multiple sclerosis; three patients with clinically isolated syndrome developed multiple sclerosis after the age of 18 and were not included in the multiple sclerosis group. The gender ratio was equal. Of the nine girls, seven were diagnosed with clinically isolated syndrome. Most patients (11 of 18) were diagnosed during the period January through March. Oligoclonal bands in cerebrospinal fluid were exclusively found in patients with multiple sclerosis and clinically isolated syndrome and 13 of 14 available magnetic resonance images revealed clear abnormalities.The annual incidence of acquired demyelinating syndromes and multiple sclerosis in Iceland was 1.15/100,000 children. The risk of progression from clinically isolated syndrome to multiple sclerosis was high. There was no female preponderance.

Aim To describe trends in cerebral palsy (CP) prevalence, severity, and associated impairments among 139 Icelandic children (65 males, 74 females) born from 1990 to 1996 (period one) and 1997 to 2003 (period two). Method A population-based study using systematically collected data on motor functioning and associated impairments of children with CP. Mean age at assessment was 5 years 5 months (SD 7.68 mo) in period one and 5 years 5 months (SD 10.44mo) in period two. Infants with postneonatal CP were excluded. Results Prevalence of CP per 1000 live births was 2.2 in period one and 2.3 in period two (p=0.862); it decreased from 1.5 to 0.9 for children born at term, was stable for preterm births, but increased from 33.7 to 114.6 for very preterm births (p=0.002). Concurrently, neonatal and infant mortality rates decreased in Iceland. The proportion of children born preterm increased over time (p=0.002), whereas improvements in gross motor function assessed with the Gross Motor Function Classification System were confined to term births (p=0.009). The proportion of children with diplegia increased, accompanied by a decrease in the proportion with quadriplegia (p=0.047). Furthermore, among term births there was a significant reduction over time in the proportion of children with epilepsy (p=0.030) and in the proportion with two or more associated impairments (p=0.030). Interpretation Although CP prevalence remained stable over 14 years, we observed a decrease in prevalence and severity of the disability among term births.

Here we describe the insights gained from sequencing the whole genomes of 2,636 Icelanders to a median depth of 20×. We found 20 million SNPs and 1.5 million insertions-deletions (indels). We describe the density and frequency spectra of sequence variants in relation to their functional annotation, gene position, pathway and conservation score. We demonstrate an excess of homozygosity and rare protein-coding variants in Iceland. We imputed these variants into 104,220 individuals down to a minor allele frequency of 0.1% and found a recessive frameshift mutation in MYL4 that causes early-onset atrial fibrillation, several mutations in ABCB4 that increase risk of liver diseases and an intronic variant in GNAS associating with increased thyroid-stimulating hormone levels when maternally inherited. These data provide a study design that can be used to determine how variation in the sequence of the human genome gives rise to human diversity.