Previous studies have found a subgroup of people with autism or Asperger Syndrome who pass second-order tests of theory of mind. However, such tests have a ceiling in developmental terms corresponding to a mental age of about 6 years. It is therefore impossible to say if such individuals are intact or impaired in their theory of mind skills. We report the performance of very high functioning adults with autism or Asperger Syndrome on an adult test of theory of mind ability. The task involved inferring the mental state of a person just from the information in photographs of a person's eyes. Relative to age-matched normal controls and a clinical control group (adults with Tourette Syndrome), the group with autism and Asperger Syndrome were significantly impaired on this task. The autism and Asperger Syndrome sample was also impaired on Happé's strange stories tasks. In contrast, they were unimpaired on two control tasks: recognising gender from the eye region of the face, and recognising basic emotions from the whole face. This provides evidence for subtle mindreading deficits in very high functioning individuals on the autistic continuum.
Highlights d Three groups of highly genetically-related disorders among 8 psychiatric disorders d Identified 109 pleiotropic loci affecting more than one disorder d Pleiotropic genes show heightened expression beginning in 2 nd prenatal trimester d Pleiotropic genes play prominent roles in neurodevelopmental processes Authors Cross-Disorder Group of the Psychiatric Genomics Consortium
Tourette syndrome (TS) is characterized by multiple motor tics plus one or more vocal (phonic) tics, which characteristically wax and wane. It can no longer be considered the rare and bizarre syndrome that it was once thought to be. The concepts surrounding TS, and our understanding of it, are also becoming increasingly complex and, in some individuals, TS is now recognized to be associated with a wide variety of associated behaviours and psychopathologies. It is suggested that TS is heterogeneous from a variety of standpoints including clinical presentation and psychopathology, and thus neuropharmacological responses and possibly even aetiological and genetic mechanisms. In this paper, mention is made of recent findings in epidemiology and genetics, highlighting the complexities of the disorder; these have been chosen because findings in both areas have clinical and management implications. The literature on the clinical manifestations, associated behaviours, psychopathology (and/or comorbid conditions) and management, in particular, is reviewed in detail.
Disorders of the brain can exhibit considerable epidemiological comorbidity and often share symptoms, provoking debate about their etiologic overlap. We quantified the genetic sharing of 25 brain disorders from genome-wide association studies of 265,218 patients and 784,643 control participants and assessed their relationship to 17 phenotypes from 1,191,588 individuals. Psychiatric disorders share common variant risk, whereas neurological disorders appear more distinct from one another and from the psychiatric disorders. We also identified significant sharing between disorders and a number of brain phenotypes, including cognitive measures. Further, we conducted simulations to explore how statistical power, diagnostic misclassification, and phenotypic heterogeneity affect genetic correlations. These results highlight the importance of common genetic variation as a risk factor for brain disorders and the value of heritability-based methods in understanding their etiology.
We have established a multisite, international database of 3,500 individuals diagnosed with Tourette syndrome (TS). The male:female ratio is 4.3:1 for the total sample, with wide variation among sites; the male excess occurs at every site. Anger control problems, sleep difficulties, coprolalia, and self-injurious behavior only reach impressive levels in individuals with comorbidity. Anger control problems are strongly correlated with comorbidity, regardless of site, region, or whether assessed by neurologists or psychiatrists. The mean age at onset of tics is 6.4 years. At all ages, about 12% of individuals with TS have no reported comorbidity. The most common reported comorbidity is attention-deficit-hyperactivity disorder. Males are more likely to have comorbid disorders than females. The earlier the age at onset, the greater the likelihood of a positive family history of tics. An understanding of the factors producing these and other variations might assist in better subtyping of TS. Because behavioral problems are associated with comorbidity, their presence should dictate a high index of suspicion of the latter, whose treatment may be at least as important as tic reduction. The established database can be used as the entry point for further research when large samples are studied and generalizability of results is important.
We have established a multisite, international database of 3500 individuals diagnosed with Tourette syndrome (TS). The male:female ratio is 4.3:1 for the total sample, with wide variation among sites; the male excess occurs at every site. Anger control problems, sleep difficulties, coprolalia, and self‐injurious behavior only reach impressive levels in individuals with comorbidity. Anger control problems are strongly correlated with comorbidity, regardless of site, region, or whether assessed by neurologists or psychiatrists. The mean age at onset of tics is 6.4 years. At all ages, about 12% of individuals with TS have no reported comorbidity. The most common reported comorbidity is attention‐deficit‐hyperactivity disorder. Males are more likely to have comorbid disorders than females. The earlier the age at onset, the greater the likelihood of a positive family history of tics. An understanding of the factors producing these and other variations might assist in better subtyping of TS. Because behavioral problems are associated with comorbidity, their presence should dictate a high index of suspicion of the latter, whose treatment may be at least as important as tic reduction. The established database can be used as the entry point for further research when large samples are studied and generalizability of results is important.
The direct estimation of heritability from genome-wide common variant data as implemented in the program Genome-wide Complex Trait Analysis (GCTA) has provided a means to quantify heritability attributable to all interrogated variants. We have quantified the variance in liability to disease explained by all SNPs for two phenotypically-related neurobehavioral disorders, obsessive-compulsive disorder (OCD) and Tourette Syndrome (TS), using GCTA. Our analysis yielded a heritability point estimate of 0.58 (se = 0.09, p = 5.64e-12) for TS, and 0.37 (se = 0.07, p = 1.5e-07) for OCD. In addition, we conducted multiple genomic partitioning analyses to identify genomic elements that concentrate this heritability. We examined genomic architectures of TS and OCD by chromosome, MAF bin, and functional annotations. In addition, we assessed heritability for early onset and adult onset OCD. Among other notable results, we found that SNPs with a minor allele frequency of less than 5% accounted for 21% of the TS heritability and 0% of the OCD heritability. Additionally, we identified a significant contribution to TS and OCD heritability by variants significantly associated with gene expression in two regions of the brain (parietal cortex and cerebellum) for which we had available expression quantitative trait loci (eQTLs). Finally we analyzed the genetic correlation between TS and OCD, revealing a genetic correlation of 0.41 (se = 0.15, p = 0.002). These results are very close to previous heritability estimates for TS and OCD based on twin and family studies, suggesting that very little, if any, heritability is truly missing (i.e., unassayed) from TS and OCD GWAS studies of common variation. The results also indicate that there is some genetic overlap between these two phenotypically-related neuropsychiatric disorders, but suggest that the two disorders have distinct genetic architectures.
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