A systematic review and meta-analysis of the long-term overall outcome of autism spectrum disorders in adolescence and adulthood.

OBJECTIVE: A systematic review and meta-analysis of studies reporting on the overall outcome in terms of a global measure of adjustment in children with autistic disorders followed up in adolescence and adulthood. METHOD: PubMed, PsycINFO, and EMBASE were systematically searched on 3rd of August 2015. Included studies were analyzed using random-effects models estimating event rates (%) and 95% confidence intervals (95%CI). RESULTS: From 4350 records identified in the search, 15 studies covering 12 unique samples and a total of N = 828 individuals with autistic disorders were included in the analyses. An estimated 19.7% (95%CI: 14.2-26.6) had a good outcome, 31.1% (95%CI: 23.2-40.4%) a fair outcome, and 47.7% (95%CI: 36.6-59.0) a poor outcome. The meta-analysis showed strong evidence for heterogeneity. The subtype of childhood autism is a significant moderating factor on the risk of having a poor outcome at follow-up, whereas age at follow-up showed statistically significant but inconsistent associations with outcome status. CONCLUSION: The long-term outcome of almost half of all individuals with autistic disorders is poor. The subtype of autism in childhood may be a predictor for specific long-term outcomes, but in general, little is known about the pathways and predictors.

A genome-wide search for alleles and haplotypes associated with autism and related pervasive developmental disorders on the Faroe Islands.

The involvement of genetic factors in the etiology of autism has been clearly established. We undertook a genome-wide search for regions containing susceptibility genes for autism in 12 subjects with childhood autism and related pervasive developmental disorders (PDDs) and 44 controls from the relatively isolated population of the Faroe Islands. In total, 601 microsatellite markers distributed throughout the human genome with an average distance of 5.80 cM were genotyped, including 502 markers in the initial scan. The Faroese population structure and genetic relatedness of cases and controls were also evaluated. Based on a combined approach, including an assumption-free test as implemented in CLUMP, Fisher's exact test for specific alleles and haplotypes, and IBD(0) probability calculations, we found association between autism and microsatellite markers in regions on 2q, 3p, 6q, 15q, 16p, and 18q. The most significant finding was on 3p25.3 (P(T1)=0.00003 and P(T4)=0.00007), which was also supported by other genetic studies. Furthermore, no evidence of population substructure was found, and a higher degree of relatedness among cases could not be detected, decreasing the risk of inflated P-values. Our data suggest that markers in these regions are in linkage disequilibrium with genes involved in the etiology of autism, and we hypothesize susceptibility genes for autism and related PDDs to be localized within these regions.

The incidence and prevalence of pervasive developmental disorders: a Danish population-based study.

BACKGROUND: Based on prevalence studies and the few incidence studies of pervasive developmental disorders (PDDs) the prevalence and incidence of these disorders have been claimed to be increasing. METHOD: The annual and age-specific prevalence and incidence rates of childhood autism, atypical autism, Asperger's disorder, and pervasive developmental disorder not otherwise specified (PDD-NOS) in Denmark during the period 1971--2000 in children younger than 10 years were estimated using data from the Danish Psychiatric Central Register. RESULTS: A total of 2.4 million children younger than 10 years were followed and 2061 cases with the PDDs studied were identified. Generally, the prevalence and incidence rates of the PDDs studied were stable until the early 1990s after which an increase in the occurrence of all disorders was seen, until 2000. The annual incidence rate per 10000 children younger than 10 years was 2.0 for childhood autism, 0.7 for atypical autism, 1.4 for Asperger's disorder, and 3.0 for PDD-NOS in 2000. We calculated a 'corrected' prevalence of childhood autism at 11.8, atypical autism at 3.3, Asperger's disorder at 4.7, and PDD-NOS at 14.6 per 10,000 children younger than 10 years on 1 January 2001. CONCLUSIONS: We found that the estimated prevalences of the PDDs studied were probably underestimated. Furthermore, the increasing prevalence and incidence rates during the 1990s may well be explained by changes in the registration procedures and more awareness of the disorders, although a true increase in the incidence cannot be ruled out.