The number of genes associated with autism is increasing, but few studies have been performed on epidemiological cohorts and in isolated populations. Here, we investigated 357 individuals from the Faroe Islands including 36 individuals with autism, 136 of their relatives and 185 non-autism controls. Data from SNP array and whole exome sequencing revealed that individuals with autism had a higher burden of rare exonic copy-number variants altering autism associated genes (deletions (p = 0.0352) or duplications (p = 0.0352)), higher inbreeding status (p = 0.023) and a higher load of rare homozygous deleterious variants (p = 0.011) compared to controls. Our analysis supports the role of several genes/loci associated with autism (e.g., NRXN1, ADNP, 22q11 deletion) and identified new truncating (e.g., GRIK2, ROBO1, NINL, and IMMP2L) or recessive deleterious variants (e.g., KIRREL3 and CNTNAP2) affecting autism-associated genes. It also revealed three genes involved in synaptic plasticity, RIMS4, KALRN, and PLA2G4A, carrying de novo deleterious variants in individuals with autism without intellectual disability. In summary, our analysis provides a better understanding of the genetic architecture of autism in isolated populations by highlighting the role of both common and rare gene variants and pointing at new autism-risk genes. It also indicates that more knowledge about how multiple genetic hits affect neuronal function will be necessary to fully understand the genetic architecture of autism.

Vitamin D deficiency has been proposed as a possible risk factor for developing autism spectrum disorder (ASD). 25-Hydroxyvitamin D3 (25(OH)D3) levels were examined in a cross-sectional population-based study in the Faroe Islands. The case group consisting of a total population cohort of 40 individuals with ASD (aged 15–24 years) had significantly lower 25(OH)D3 than their 62 typically-developing siblings and their 77 parents, and also significantly lower than 40 healthy age and gender matched comparisons. There was a trend for males having lower 25(OH)D3 than females. Effects of age, month/season of birth, IQ, various subcategories of ASD and Autism Diagnostic Observation Schedule score were also investigated, however, no association was found. The very low 25(OH)D3 in the ASD group suggests some underlying pathogenic mechanism.

We have followed up a 2002 population study of autism prevalence in 15-24-year olds in the Faroe Islands. The rate of ASD grew significantly from 0.56% in 2002 to 0.94% in 2009. Although these results are within the range of typical findings from other studies, there were some interesting details. There were-in addition to 43 originally diagnosed cases in 2002-24 newly discovered cases in 2009 and nearly half of them were females. It is possible that unfamiliarity with the clinical presentation of autism in females have played a significant role in this context. There was diagnostic stability for the overall category of ASD over time in the group diagnosed in childhood (7-16) years, but considerable variability as regards diagnostic sub-groupings.

Background:Dementia has become an important public health, economic, and social issue. Knowledge about prevalence, incidence, and trends of dementia in a country is of crucial importance. However, no studies of incidence or prevalence of dementia have been undertaken in the Faroe Islands.Objectives:The aim was to estimate the overall and trend in incidence and prevalence of dementia among individuals ≥60 years in the Faroe Islands from 2010-2017.Methods:Population-based register study where all individuals ≥60 years with a dementia diagnosis from January 2010 to December 2017 were identified. The overall crude and age-and-sex-specific incidence and prevalence was assessed.Results:The overall crude incidence among individuals ≥60 years from 2010 to 2017 was 5.1 per 1000 individuals and the prevalence 22.5 per 1000 individuals. The age-and sex-standardized annual incidence of dementia fluctuated between 4.8 and 6.7 per 1000, with no clear secular trend while the age-and sex-standardized prevalence increased steadily from 14.5 in 2010 to 30.8 per 1000 individuals in 2017.Conclusion:The age-standardized incidence or prevalence estimates in the Faroes seem to be lower than in other countries. The incidence was relatively stable in the period while the prevalence of dementia simultaneously increased.

Childhood autism or autism spectrum disorder (ASD) has been regarded as one of the most stable diagnostic categories applied to young children with psychiatric/developmental disorders. The stability over time of a diagnosis of ASD is theoretically interesting and important for various diagnostic and clinical reasons. We studied the diagnostic stability of ASD from childhood to early adulthood in the Faroe Islands: a total school age population sample (8–17-year-olds) was screened and diagnostically assessed for AD in 2002 and 2009. This paper compares both independent clinical diagnosis and Diagnostic Interview for Social and Communication Disorders (DISCO) algorithm diagnosis at two time points, separated by seven years. The stability of clinical ASD diagnosis was perfect for AD, good for “atypical autism”/PDD-NOS, and less than perfect for Asperger syndrome (AS). Stability of the DISCO algorithm subcategory diagnoses was more variable but still good for AD. Both systems showed excellent stability over the seven-year period for “any ASD” diagnosis, although a number of clear cases had been missed at the original screening in 2002. The findings support the notion that subcategories of ASD should be collapsed into one overarching diagnostic entity with subgrouping achieved on other “non-autism” variables, such as IQ and language levels and overall adaptive functioning.

The aim of the study was to elucidate some supposed core features of suicide through a study of suicide in a low-incidence population. The material covered all suicides and undetermined deaths 1945-2004 in the Faroe Islands (a low-incidence population) and the study made use of all available information. Results showed that suicide rate had been low since the Second World War. However, there was an increase throughout the 1970s and 1980s. Supposed core features of suicide, such as gender, marital status, former psychiatric admittance, former suicidal behaviour, alcohol and method preference were confirmed. Others were not, such as an increasing rate with old age. In diagnostics, the role of psychiatric disorders was confirmed, but so was a substantial role of "no disorder". Increase period revealed a high proportion of cases with alcohol involved and a substantial part included males, in age groups 25-64 years, unmarried, divorced and alcohol intoxicated. The main conclusion was that a low-incidence population of suicide population confirmed some supposed core features of the suicide phenomenon. Others, related to age and psychiatric disorders, were only partially confirmed. In periods of increase, the most vulnerable were the young and middle-aged males, unmarried, divorced, and alcohol played a crucial role.

The number of genes associated with autism is increasing, but few studies have been performed on epidemiological cohorts and in isolated populations. Here, we investigated 357 individuals from the Faroe Islands including 36 individuals with autism, 136 of their relatives and 185 non-autism controls. Data from SNP array and whole exome sequencing revealed that individuals with autism compared to controls had a higher burden of copynumber variants (p < 0.05), higher inbreeding status (p < 0.005) and higher load of homozygous deleterious variants (p < 0.01). Our analysis supports the role of several genes/loci associated with autism (e.g. NRXN1, ADNP, 22q11 deletion) and identified new truncating (e.g. GRIK2, ROBO1, NINL and IMMP2L) or recessive deleterious variants (e.g. KIRELL3 and CNTNAP2) affecting autism-risk genes. It also revealed three genes involved in synaptic plasticity, RIMS4, KALRN and PLA2G4A, carrying de novo deleterious variants in individuals with autism without intellectual disability. In summary, our analysis provides a better understanding of the genetic architecture of autism in isolated populations by highlighting the role of both common and rare gene variants and pointing at new autism-risk genes. It also indicates that more knowledge about how multiple genetic hits affect neuronal function will be necessary to fully understand the genetic architecture of autism.

The greatest genetic risk factor for Alzheimer's disease (AD) is the apolipoprotein E (APOE) ε4 allele [1]. During the last decade, more than 40 additional AD-associated risk variants have been identified, mostly through genome-wide association studies (GWAS) [2-6]. Although these disease-associated alleles/loci confer marginal risk, they have illuminated biological mechanisms underlying disease. Polygenic risk scores (PRSs) proxy the genetic liability of an individual to disease and are based on the weighted sum of genome-wide