What is Known About Autism

Child and adolescent psychiatric genetics

The current status of child and adolescent psychiatric genetics appears promising in light of the initiation of genome-wide association studies (GWAS) for diverse polygenic disorders and the molecular elucidation of monogenic Rett syndrome, for which recent functional studies provide hope for pharmacological treatment strategies. Within the last 50 years, tremendous progress has been made in linking genetic variation to behavioral phenotypes and psychiatric disorders. We summarize the major findings of the Human Genome Project and dwell on largely unsuccessful candidate gene and linkage studies. GWAS for the first time offer the possibility to detect single nucleotide polymorphisms and copy number variants without a priori hypotheses as to their molecular etiology. At the same time it is becoming increasingly clear that very large sample sizes are required in order to enable genome wide significant findings, thus necessitating further large-scaled ascertainment schemes for the successful elucidation of the molecular genetics of childhood and adolescent psychiatric disorders. We conclude by reflecting on different scenarios for future research into the molecular basis of early onset psychiatric disorders. This review represents the introductory article of this special issue of the European Child and Adolescent Psychiatry.

Neurofeedback for autistic spectrum disorder: a review of the literature

There is a need for effective interventions to address the core symptoms and problems associated with autistic spectrum disorder (ASD). Behavior therapy improves communication and behavioral functioning. Additional treatment options include psychopharmacological and biomedical interventions. Although these approaches help children with autistic problems, they may be associated with side effects, risks or require ongoing or long-term treatment. Neurofeedback is a noninvasive approach shown to enhance neuroregulation and metabolic function in ASD. We present a review of the literature on the application of Neurofeedback to the multiple problems associated with ASD. Directions for future research are discussed.

Novel clustering of items from the Autism Diagnostic Interview-Revised to define phenotypes within autism spectrum disorders

Heterogeneity in phenotypic presentation of Autism spectrum disorders has been cited as one explanation for the difficulty in pinpointing specific genes involved in autism. Recent studies have attempted to reduce the "noise" in genetic and other biological data by reducing the phenotypic heterogeneity of the sample population. The current study employs multiple clustering algorithms on 123 item scores from the Autism Diagnostic Interview-Revised (ADI-R) diagnostic instrument of nearly 2,000 autistic individuals to identify subgroups of autistic probands with clinically relevant behavioral phenotypes in order to isolate more homogeneous groups of subjects for gene expression analyses. Our combined cluster analyses suggest optimal division of the autistic probands into four phenotypic clusters based on similarity of symptom severity across the 123 selected item scores. One cluster is characterized by severe language deficits, while another exhibits milder symptoms across the domains. A third group possesses a higher frequency of savant skills while the fourth group exhibited intermediate severity across all domains. Grouping autistic individuals by multivariate cluster analysis of ADI-R scores reveals meaningful phenotypes of subgroups within the autistic spectrum, which we show, in a related (accompanying) study, to be associated with distinct gene expression profiles.

Prenatal risk factors for autism: comprehensive meta-analysis

BACKGROUND

The aetiology of autism is unknown, although prenatal exposures have been the focus of epidemiological research for over 40 years.

AIMS

To provide the first quantitative review and meta-analysis of the association between maternal pregnancy complications and pregnancy-related factors and risk of autism.

METHOD

PubMed, Embase and PsycINFO databases were searched for epidemiological studies that examined the association between pregnancy-related factors and autism. Forty studies were eligible for inclusion in the meta-analysis. Summary effect estimates were calculated for factors examined in multiple studies.

RESULTS

Over 50 prenatal factors have been examined. The factors associated with autism risk in the meta-analysis were advanced parental age at birth, maternal prenatal medication use, bleeding, gestational diabetes, being first born v. third or later, and having a mother born abroad. The factors with the strongest evidence against a role in autism risk included previous fetal loss and maternal hypertension, proteinuria, pre-eclampsia and swelling.

CONCLUSIONS

There is insufficient evidence to implicate any one prenatal factor in autism aetiology, although there is some evidence to suggest that exposure to pregnancy complications may increase the risk.

Gene expression profiling of lymphoblasts from autistic and nonaffected sib pairs: altered pathways in neuronal development and steroid biosynthesis

Despite the identification of numerous autism susceptibility genes, the pathobiology of autism remains unknown. The present “case-control” study takes a global approach to understanding the molecular basis of autism spectrum disorders based upon large-scale gene expression profiling. DNA microarray analyses were conducted on lymphoblastoid cell lines from over 20 sib pairs in which one sibling had a diagnosis of autism and the other was not affected in order to identify biochemical and signaling pathways which are differentially regulated in cells from autistic and nonautistic siblings. Bioinformatics and gene ontological analyses of the data implicate genes which are involved in nervous system development, inflammation, and cytoskeletal organization, in addition to genes which may be relevant to gastrointestinal or other physiological symptoms often associated with autism. Moreover, the data further suggests that these processes may be modulated by cholesterol/steroid metabolism, especially at the level of androgenic hormones. Elevation of male hormones, in turn, has been suggested as a possible factor influencing susceptibility to autism, which affects ∼4 times as many males as females. Preliminary metabolic profiling of steroid hormones in lymphoblastoid cell lines from several pairs of siblings reveals higher levels of testosterone in the autistic sibling, which is consistent with the increased expression of two genes involved in the steroidogenesis pathway. Global gene expression profiling of cultured cells from ASD probands thus serves as a window to underlying metabolic and signaling deficits that may be relevant to the pathobiology of autism.

Neural and genetic foundations of face recognition and prosopagnosia

Faces are of essential importance for human social life. They provide valuable information about the identity, expression, gaze, health, and age of a person. Recent face-processing models assume highly interconnected neural structures between different temporal, occipital, and frontal brain areas with several feedback loops. A selective deficit in the visual learning and recognition of faces is known as prosopagnosia, which can be found both in acquired and congenital form. Recently, a hereditary sub-type of congenital prosopagnosia with a very high prevalence rate of 2.5% has been identified. Recent research results show that hereditary prosopagnosia is a clearly circumscribed face-processing deficit with a characteristic set of clinical symptoms. Comparing face processing of people of prosopagnosia with that of controls can help to develop a more conclusive and integrated model of face processing. Here, we provide a summary of the current state of face processing research. We also describe the different types of prosopagnosia and present the set of typical symptoms found in the hereditary type. Finally, we will discuss the implications for future face recognition research.

Social competence and social skills training and intervention for children with Autism Spectrum Disorders

This study examined the effectiveness of a 30 week social competence and social skills group intervention program with children, ages 7-11, diagnosed with Autism Spectrum Disorders (ASD). Eighteen children with ASD were assessed with pretreatment and posttreatment measures on the Walker-McConnell Scale (WMS) and the MGH YouthCare Social Competence Development Scale. Each received the 30-week intervention program. For comparison, a matched sample of ten non-ASD children was also assessed, but received no treatment. The findings indicated that each ASD intervention group demonstrated significant gains on the WMS and significant improvement in the areas of anxiety management, joint attention, and flexibility/transitions. Results suggest that this approach can be effective in improving core social deficits in individuals with ASD.

Metabolic biomarkers related to oxidative stress and antioxidant status in Saudi autistic children

OBJECTIVE

Measurement of oxidative stress and antioxidant-related parameters (enzymatic and non-enzymatic) in Saudi autistic children.

DESIGN AND METHODS

30 autistic children (22 males and 8 females) aged 3-15 years (25/30 of these were below 8 years old), and 30 healthy children as control group were included in this study. Levels of lipid peroxides, vitamin E, vitamin C, glutathione together with enzymatic activities of glutathione peroxidase (GSH-Px), and catalase were determined in plasma while superoxide dismutase (SOD was measured in red blood cells of both groups.

RESULTS

Lipid peroxidation was found to be significantly higher in autistic compared to control Saudi children. On the other hand, vitamin E and glutathione were remarkably lower in autistic patients while vitamin C shows non-significant lower values. Regarding the enzymatic antioxidants, both glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were significantly higher in autistic compared to control while catalase recorded more or less similar activities in both groups.

CONCLUSION

Saudi autistic children are under H(2)O(2) stress due to GSH depletion, over expression of SOD together with the unchanged catalase enzyme. This could be helpful in the early diagnosis of young autistic patients and suggesting the possibility of antioxidant supplementation for the early intervention with autistic children.

Ockham's Razor and autism: the case for developmental neurotoxins contributing to a disease of neurodevelopment

Much professional awareness regarding environmental triggers for ASD has been narrowly focused on a single possible exposure pathway (vaccines). Meanwhile, empirical support for environmental toxins as a broad class has been quietly accumulating. Recent research has shown that persons with ASD have comparatively higher levels of various toxins and are more likely to have reduced detoxifying ability, and, that rates of ASD may be higher in areas with greater pollution. This report documents that within the state with the highest rate of ASD, the rate is higher for schools near EPA Superfund sites, t (332)=3.84, p=.0001. The reasons for the rise in diagnoses likely involve genetically predisposed individuals being exposed to various environmental triggers at higher rates than in past generations.

Regulation of cerebral cortical size and neuron number by fibroblast growth factors: implications for autism

Increased brain size is common in children with autism spectrum disorders. Here we propose that an increased number of cortical excitatory neurons may underlie the increased brain volume, minicolumn pathology and excessive network excitability, leading to sensory hyper-reactivity and seizures, which are often found in autism. We suggest that Fibroblast Growth Factors (FGF), a family of genes that regulate cortical size and connectivity, may be responsible for these developmental alterations. Studies in animal models suggest that mutations in FGF genes lead to altered cortical volume, excitatory cortical neuron number, minicolumn pathology, hyperactivity and social deficits. Thus, many risk factors may converge upon FGF-regulated pathogenetic pathways, which alter excitatory/inhibitory balance and cortical modular architecture, and predispose to autism spectrum disorders.

Eagle-eyed visual acuity: an experimental investigation of enhanced perception in autism

BACKGROUND

Anecdotal accounts of sensory hypersensitivity in individuals with autism spectrum conditions (ASC) have been noted since the first reports of the condition. Over time, empirical evidence has supported the notion that those with ASC have superior visual abilities compared with control subjects. However, it remains unclear whether these abilities are specifically the result of differences in sensory thresholds (low-level processing), rather than higher-level cognitive processes.

METHODS

This study investigates visual threshold in n = 15 individuals with ASC and n = 15 individuals without ASC, using a standardized optometric test, the Freiburg Visual Acuity and Contrast Test, to investigate basic low-level visual acuity.

RESULTS

Individuals with ASC have significantly better visual acuity (20:7) compared with control subjects (20:13)-acuity so superior that it lies in the region reported for birds of prey.

CONCLUSIONS

The results of this study suggest that inclusion of sensory hypersensitivity in the diagnostic criteria for ASC may be warranted and that basic standardized tests of sensory thresholds may inform causal theories of ASC.

Experimental evidence that the serotonin transporter mediates serotonin accumulation in LSO neurons of the postnatal mouse

During the same postnatal period of development when their terminal projection patterns in the midbrain are maturing, lateral superior olivary (LSO) neurons are immunoreactive for serotonin (5-HT). As there is no evidence that LSO neurons synthesize 5-HT, it is likely that they accumulate 5-HT via the 5-HT transporter. To determine if the 5-HT transporter is responsible for 5-HT inside postnatal mouse LSO neurons, pups (postnatal ages 5-6) were treated with fluoxetine and LSO neurons examined for 5-HT. We also evaluated whether LSO neurons containing 5-HT expressed the 5-HT transporter. To further rule out any potential synthesis of 5-HT, brainstem sections of mice at postnatal ages when 5-HT staining is the most robust were stained for the rate-limiting enzyme in the synthesis of 5-HT, tryptophan hydroxylase. Fluoxetine treatment reduced or in most cases, completely eliminated the number of neurons in the LSO stained for 5-HT. Postnatal LSO neurons containing 5-HT were immunoreactive for the 5-HT transporter; in older animals in which 5-HT was no longer observed in the LSO neurons, 5-HT transporter expression was similarly absent. Further, LSO neurons in mice at any age did not stain for tryptophan hydroxylase. These results indicate that LSO neurons express the functional 5-HT transporter to internalize 5-HT; this mechanism may serve to regulate extracellular 5-HT levels during maturation of their terminal endings in the inferior colliculus.

Genomic imprinting in the development and evolution of psychotic spectrum conditions

I review and evaluate genetic and genomic evidence salient to the hypothesis that the development and evolution of psychotic spectrum conditions have been mediated in part by alterations of imprinted genes expressed in the brain. Evidence from the genetics and genomics of schizophrenia, bipolar disorder, major depression, Prader-Willi syndrome, Klinefelter syndrome, and other neurogenetic conditions support the hypothesis that the etiologies of psychotic spectrum conditions commonly involve genetic and epigenetic imbalances in the effects of imprinted genes, with a bias towards increased relative effects from imprinted genes with maternal expression or other genes favouring maternal interests. By contrast, autistic spectrum conditions, including Kanner autism, Asperger syndrome, Rett syndrome, Turner syndrome, Angelman syndrome, and Beckwith-Wiedemann syndrome, commonly engender increased relative effects from paternally expressed imprinted genes, or reduced effects from genes favouring maternal interests. Imprinted-gene effects on the etiologies of autistic and psychotic spectrum conditions parallel the diametric effects of imprinted genes in placental and foetal development, in that psychotic spectrum conditions tend to be associated with undergrowth and relatively-slow brain development, whereas some autistic spectrum conditions involve brain and body overgrowth, especially in foetal development and early childhood. An important role for imprinted genes in the etiologies of psychotic and autistic spectrum conditions is consistent with neurodevelopmental models of these disorders, and with predictions from the conflict theory of genomic imprinting.

Autism and serotonin transporter gene polymorphisms: a systematic review and meta-analysis

The serotonin transporter gene (5-HTT) plays a crucial role in serotonergic neurotransmission and has been found to be associated, with varying degrees of significance, with many diseases, including autism. Prior association studies of autism have yielded conflicting results regarding the association between two common 5-HTT polymorphisms, the promoter insertion/deletion (5-HTTLPR) and the intron 2 VNTR (STin2 VNTR). We conducted a systematic review and meta-analysis to test the following hypotheses: (i) there is an association between autism and either or both of the 5-HTTLPR and STin2 VNTR polymorphisms, and (ii) the S allele of 5-HTTLPR and/or the STin2.12 allele of the VNTR are the specific risk alleles for autism. All published family-based and population based studies were examined to determine the overall strength of association between 5-HTT polymorphisms and autism. After exclusion of studies with overlapping samples and studies whose data did not allow for calculation of an odds ratio, 16 studies were included for final analyses, all but two of which used a family-based design. The meta-analysis failed to find a significant overall association between either of the 5-HTT polymorphisms examined and autism. Further, no allelic transmission distortion was found when studies of simplex (11 studies) and multiplex (3 studies) family samples were analyzed separately. However, there was significant heterogeneity by ethnicity; family based studies of US mixed population samples showed preferential transmission of the S allele of 5-HTTLPR (S allele:L allele = 247:183), while there was no allelic distortion among the family-based studies of European and Asian samples.

Effect of the atypical neuroleptic risperidone on morphology and S100B secretion in C6 astroglial lineage cells

We investigated the effect of the atypical neuroleptic risperidone on morphology and S100B secretion in C6 glioma cells, considering the putative involvement of astroglial cells in neuropsychiatric disorders. In the presence of high experimental doses of risperidone, C6 cells become stellate, with process-bearing cells and partial retraction of the cell body followed by detachment from the adhesion surface with practically no cell death. These results indicate that risperidone is able to interfere with C6 cell adhesion without toxic effects. RhoA activator LPA prevented the effects of risperidone on cell morphology. From 6 h risperidone induced a statistically significant increment of about 80% in S100B secretion. These data contribute to the proposal that glial cells are targets of risperidone, which could be involved in the therapeutic response of risperidone to improve autism symptoms.

Experiential and genetic contributions to depressive- and anxiety-like disorders: clinical and experimental studies

Stressful events have been implicated in the precipitation of depression and anxiety. These disorders may evolve owing to one or more of an array of neuronal changes that occur in several brain regions. It seems likely that these stressor-provoked neurochemical alterations are moderated by genetic determinants, as well as by a constellation of experiential and environmental factors. Indeed, animal studies have shown that vulnerability to depressive-like behaviors involve mechanisms similar to those associated with human depression (e.g., altered serotonin, corticotropin releasing hormone and their receptors, growth factors), and that the effects of stressors are influenced by previous stressor experiences, particularly those encountered early in life. These stressor effects might reflect sensitization of neuronal functioning, phenotypic changes of processes that lead to neurochemical release or receptor sensitivity, or epigenetic processes that modify expression of specific genes associated with stressor reactivity. It is suggested that depression is a life-long disorder, which even after effective treatment, has a high rate of re-occurrence owing to sensitized processes or epigenetic factors that promote persistent alterations of gene expression.

Gabrb3 gene deficient mice exhibit impaired social and exploratory behaviors, deficits in non-selective attention and hypoplasia of cerebellar vermal lobules: a potential model of autism spectrum disorder

OBJECTIVE

GABA(A) receptors play an important regulatory role in the developmental events leading to the formation of complex neuronal networks and to the behaviors they govern. The primary aim of this study was to assess whether gabrb3 gene deficient (gabrb3(-/-)) mice exhibit abnormal social behavior, a core deficit associated with autism spectrum disorder.

METHODS

Social and exploratory behaviors along with non-selective attention were assessed in gabrb3(-/-), littermates (gabrb3(+/+)) and progenitor strains, C57BL/6J and 129/SvJ. In addition, semi-quantitative assessments of the size of cerebellar vermal lobules were performed on gabrb3(+/+) and gabrb3(-/-) mice.

RESULTS

Relative to controls, gabrb3(-/-) mice exhibited significant deficits in activities related to social behavior including sociability, social novelty and nesting. In addition, gabrb3(-/-) mice also exhibited differences in exploratory behavior compared to controls, as well as reductions in the frequency and duration of rearing episodes, suggested as being an index of non-selective attention. Gabrb3(-/-) mice also displayed significant hypoplasia of the cerebellar vermis compared to gabrb3(+/+) mice.

CONCLUSIONS

The observed behavioral deficits, especially regarding social behaviors, strengthens the face validity of the gabrb3 gene deficient mouse as being a model of autism spectrum disorder.

Children with learning disabilities

Children with learning disabilities can present numerous challenges in the acute hospital setting. This review article examines the causes and presentations of learning disability, and considers some of the management strategies employed when these children present for surgery.

Disruption of neurexin 1 associated with autism spectrum disorder

Autism is a neurodevelopmental disorder of complex etiology in which genetic factors play a major role. We have implicated the neurexin 1 (NRXN1) gene in two independent subjects who display an autism spectrum disorder (ASD) in association with a balanced chromosomal abnormality involving 2p16.3. In the first, with karyotype 46,XX,ins(16;2)(q22.1;p16.1p16.3)pat, NRXN1 is directly disrupted within intron 5. Importantly, the father possesses the same chromosomal abnormality in the absence of ASD, indicating that the interruption of alpha-NRXN1 is not fully penetrant and must interact with other factors to produce ASD. The breakpoint in the second subject, with 46,XY,t(1;2)(q31.3;p16.3)dn, occurs approximately 750 kb 5' to NRXN1 within a 2.6 Mb genomic segment that harbors no currently annotated genes. A scan of the NRXN1 coding sequence in a cohort of ASD subjects, relative to non-ASD controls, revealed that amino acid alterations in neurexin 1 are not present at high frequency in ASD. However, a number of rare sequence variants in the coding region, including two missense changes in conserved residues of the alpha-neurexin 1 leader sequence and of an epidermal growth factor (EGF)-like domain, respectively, suggest that even subtle changes in NRXN1 might contribute to susceptibility to ASD.

For others: Epistasis and the evolutionary survival of an extreme tail of the quantitative distribution of autistic assets

The ongoing paradigm shift from the traditional qualitative dichotomy concept to the quantitative framework increases the necessity of an evolutionary implication and interpretation of the presence of a hypo-reproductive behavioral extreme (autism) with strong genetic contribution. As a theoretical challenge to explain the survival of the dimensional distribution of autistic traits, an epistasis-associated oscillation of fitness outcomes is proposed. In this hypothesis, an allele could contribute to the existence of both phenotypic extreme tails and the hypothesized genetic machinery (quantitative trait loci) for autism would necessarily be common in the entire human population. The postulated autism genes would allow autistics to enjoy autistic traits and assets and all of the residual non-autistic individuals could owe their social skills and reproductive advantages to the same autism genes. Importantly, the reported modest correlations between core autistic dimensions can be illustrated using unsynchronized epistatic pleiotropy.

Autism in African American families: clinical-phenotypic findings

Unlike other complex diseases, the study of autism has been almost exclusively limited to Caucasian families. This study represents a first effort to examine clinical and phenotypic findings in individuals with autism from African American families. Drawing from an ongoing genetic study of autism we compared African American (N = 46, mean age = 118 months) and Caucasian (N = 298, mean age = 105 months) groups on autism symptoms and developmental language symptoms. The African American group showed greater delays in language but did not differ from the Caucasian group on core autism symptoms. These findings, while suggestive of a more severe phenotype, may reflect an ascertainment bias. Nonetheless, we believe that more studies of racial-ethnic groups should be conducted with several goals in mind including strengthening recruiting strategies to include more ethnic-racial groups and more thoughtful evaluation of phenotypic traits. Such considerations will aid greatly in the search for genetic variants in autism.

Multifactor dimensionality reduction-phenomics: a novel method to capture genetic heterogeneity with use of phenotypic variables

Complex human diseases do not have a clear inheritance pattern, and it is expected that risk involves multiple genes with modest effects acting independently or interacting. Major challenges for the identification of genetic effects are genetic heterogeneity and difficulty in analyzing high-order interactions. To address these challenges, we present MDR-Phenomics, a novel approach based on the multifactor dimensionality reduction (MDR) method, to detect genetic effects in pedigree data by integration of phenotypic covariates (PCs) that may reflect genetic heterogeneity. The P value of the test is calculated using a permutation test adjusted for multiple tests. To validate MDR-Phenomics, we compared it with two MDR-based methods: (1) traditional MDR pedigree disequilibrium test (PDT) without consideration of PCs (MDR-PDT) and (2) stratified phenotype (SP) analysis based on PCs, with use of MDR-PDT with a Bonferroni adjustment (SP-MDR). Using computer simulations, we examined the statistical power and type I error of the different approaches under several genetic models and sampling scenarios. We conclude that MDR-Phenomics is more powerful than MDR-PDT and SP-MDR when there is genetic heterogeneity, and the statistical power is affected by sample size and the number of PC levels. We further compared MDR-Phenomics with conditional logistic regression (CLR) for testing interactions across single or multiple loci with consideration of PC. The results show that CLR with PC has only slightly smaller power than does MDR-Phenomics for single-locus analysis but has considerably smaller power for multiple loci. Finally, by applying MDR-Phenomics to autism, a complex disease in which multiple genes are believed to confer risk, we attempted to identify multiple gene effects in two candidate genes of interest--the serotonin transporter gene (SLC6A4) and the integrin beta 3 gene (ITGB3) on chromosome 17. Analyzing four markers in SLC6A4 and four markers in ITGB3 in 117 white family triads with autism and using sex of the proband as a PC, we found significant interaction between two markers--rs1042173 in SLC6A4 and rs3809865 in ITGB3.

Association of Per1 and Npas2 with autistic disorder: support for the clock genes/social timing hypothesis

Clock gene anomalies have been suggested as causative factors in autism. We screened eleven clock/clock-related genes in a predominantly high-functioning Autism Genetic Resource Exchange sample of strictly diagnosed autistic disorder progeny and their parents (110 trios) for association of clock gene variants with autistic disorder. We found significant association (P<0.05) for two single-nucleotide polymorphisms in per1 and two in npas2. Analysis of all possible combinations of two-marker haplotypes for each gene showed that in npas2 40 out of the 136 possible two-marker combinations were significant at the P<0.05 level, with the best result between markers rs1811399 and rs2117714, P=0.001. Haplotype analysis within per1 gave a single significant result: a global P=0.027 for the markers rs2253820-rs885747. No two-marker haplotype was significant in any of the other genes, despite the large number of tests performed. Our findings support the hypothesis that these epistatic clock genes may be involved in the etiology of autistic disorder. Problems in sleep, memory and timing are all characteristics of autistic disorder and aspects of sleep, memory and timing are each clock-gene-regulated in other species. We identify how our findings may be relevant to theories of autism that focus on the amygdala, cerebellum, memory and temporal deficits. We outline possible implications of these findings for developmental models of autism involving temporal synchrony/social timing.

Coping strategies used by parents of children with autism

PURPOSE

The purpose of this research was to determine (a) the level of family adaptation, as measured by the Family Crisis Oriented Personal Evaluation Scales (F-COPESs) instrument, among persons with a child diagnosed with autism spectrum disorder (ASD) aged 12 years and under, (b) if there was a difference in F-COPES scores based on family demographics, and (c) the time lag between parent's suspicion of ASD and the actual professional diagnosis of ASD.

DATA SOURCES

A descriptive survey was used with a convenience sample derived from ASD treatment agencies and a parental support group in the California Bay Area that supports the children and parents of children with special needs.

CONCLUSIONS

Overall, the level of adaptation was within the normal limits with coping scores similar to the norm scores of the F-COPES with males scoring slightly higher than females in the coping scale. Subscale scores of the F-COPES indicated that the parents sought encouragement and support from friends, informal support from other families who faced similar problems, and formal support from agencies and programs. Reframing revealed similar results as the norm with less use of spiritual support, and more passive appraisals were noted from the parents of children with ASD. Within internal comparisons, there were no statistical differences among gender and amount of time a member spent in coordination of services. Comparisons in ethnicity for Caucasians and Asian Americans revealed a higher coping score for reframing in Asian Americans and a higher passive appraisal score among Caucasians. Non-English speakers scored higher on spiritual support, while English speakers scored higher in passive appraisals. Because of insufficient statistical power, comparisons in education, income, marital status, and relocation of residence were deferred. The time from parents' suspicions of developmental delays or disability to a professional diagnosis of ASD was at least 6 months or greater.

IMPLICATIONS FOR PRACTICE

It is imperative for nurse practitioners (NPs) to provide appropriate professional support and other social support systems to families with children with ASD. Educating parents to sound therapy approaches to provide them with the skills needed to directly address stressful events in order to increase the parent's confidence level as to avoid passive appraisals is also a crucial role of the NP. NPs may want to use the F-COPES as part of the assessment to ascertain the areas of needs of families. This study reveals the resiliency and highly adaptive nature of these parents who are under severe strain and stress of caring for a child with ASD. The effective ways they coped as a family were in the areas of informal and formal social support networks. Participants also used passive appraisal to cope. The study also supports the need for early recognition and diagnoses of ASD and referral for early intervention for better outcomes for the children and families affected by ASD.

Vasoactive intestinal peptide antagonist treatment during mouse embryogenesis impairs social behavior and cognitive function of adult male offspring

Vasoactive intestinal peptide (VIP) is a regulator of rodent embryogenesis during the period of neural tube closure. VIP enhanced growth in whole cultured mouse embryos; treatment with a VIP antagonist during embryogenesis inhibited growth and development. VIP antagonist treatment during embryogenesis also had permanent effects on adult brain chemistry and impaired social recognition behavior in adult male mice. The neurological deficits of autism appear to be initiated during neural tube closure and social behavior deficits are among the key characteristics of this disorder that is more common in males and is frequently accompanied by mental retardation. The current study examined the blockage of VIP during embryogenesis as a model for the behavioral deficits of autism. Treatment of pregnant mice with a VIP antagonist during embryonic days 8 through 10 had no apparent effect on the general health or sensory or motor capabilities of adult offspring. However, male offspring exhibited reduced sociability in the social approach task and deficits in cognitive function, as assessed through cued and contextual fear conditioning. Female offspring did not show these deficiencies. These results suggest that this paradigm has usefulness as a mouse model for aspects of autism as it selectively impairs male offspring who exhibit the reduced social behavior and cognitive dysfunction seen in autism. Furthermore, the study indicates that the foundations of some aspects of social behavior are laid down early in mouse embryogenesis, are regulated in a sex specific manner and that interference with embryonic regulators such as VIP can have permanent effects on adult social behavior.

Dissecting the locus heterogeneity of autism: significant linkage to chromosome 12q14

Autism is a common neurodevelopmental disorder with a significant genetic component and locus heterogeneity. To date, 12 microsatellite genome screens have been performed using various data sets of sib-pair families (parents and affected children) resulting in numerous regions of potential linkage across the genome. However, no universal region or consistent candidate gene from these regions has emerged. The use of large, extended pedigrees is a recognized powerful approach to identify significant linkage results, as these families potentially contain more potential linkage information than sib-pair families. A genome-wide linkage analysis was performed on 26 extended autism families (65 affected, 184 total individuals). Each family had two to four affected individuals comprised of either avuncular or cousin pairs. For analysis, we used a high-density single-nucleotide polymorphism genotyping assay, the Affymetrix GeneChip Human Mapping 10K array. Two-point analysis gave peak heterogeneity limit of detection (HLOD) of 2.82 at rs2877739 on chromosome 14q. Suggestive linkage evidence (HLOD>2) from a two-point analysis was also found on chromosomes 1q, 2q, 5q, 6p,11q and 12q. Chromosome 12q was the only region showing significant linkage evidence by multipoint analysis with a peak HLOD=3.02 at rs1445442. In addition, this linkage evidence was enhanced significantly in the families with only male affected (multipoint HLOD=4.51), suggesting a significant gender-specific effect in the etiology of autism. Chromosome-wide haplotype analyses on chromosome 12 localized the potential autism gene to a 4 cM region shared among the affected individuals across linked families. This novel linkage peak on chromosome 12q further supports the hypothesis of substantial locus heterogeneity in autism.

Genetics of obesity and the prediction of risk for health

Obesity has always existed in human populations, but until very recently was comparatively rare. The availability of abundant, energy-rich processed foods in the last few decades has, however, resulted in a sharp rise in the prevalence of obesity in westernized countries. Although it is the obesogenic environment that has resulted in this major healthcare problem, it is acting by revealing a sub-population with a pre-existing genetic predisposition to excess adiposity. There is substantial evidence for the heritability of obesity, and research in both rare and common forms of obesity has identified genes with significant roles in its aetiology. Application of this understanding to patient care has been slower. Until very recently, the health risks of obesity were thought to be well understood, with a straightforward correlation between increasing obesity and increasing risk of health problems such as type 2 diabetes, coronary heart disease, hypertension, arthritis and cancer. It is becoming clear, however, that the location of fat deposition, variation in the secretion of adipokines and other factors govern whether a particular obese person develops such complications. Prediction of the health risks of obesity for individual patients is not straightforward, but continuing advances in understanding of genetic factors influencing obesity risk and improved diagnostic technologies mean that the future for such prediction is looking increasingly bright.

The neuropathology, medical management and dental implications of autism

BACKGROUND

A paucity of information exists in the dental literature about autism and its dental implications.

TYPES OF STUDIES REVIEWED

The authors conducted a MEDLINE search for the period 2000 through 2006, using the term "autism," with the aim of defining the condition's clinical manifestations, dental and medical treatment and dental implications.

RESULTS

Autism is a severe developmental brain disorder that appears in infancy, persists throughout life, and is characterized by impaired social interaction, abnormalities in communication (both verbal and nonverbal) and restricted interests. Often accompanying the disorder are behavioral disturbances - such as self-mutilation, aggression, psychiatric symptoms and seizures - that necessitate the administration of multiple medications to help the affected person participate effectively in the educational and rehabilitative process.

CLINICAL IMPLICATIONS

Dentists caring for people with autism must be familiar with the manifestations of the disease and its associated features so that they can garner the maximum level of patient cooperation. They also must be familiar with the medications used to treat the associated features of the disorder because many of them cause untoward orofacial and systemic reactions and may precipitate adverse interactions with dental therapeutic agents.

Identification of changes in gene expression in dorsal root ganglia in diabetic neuropathy: correlation with functional deficits

This study aimed to correlate the onset of functional deficits in diabetic neuropathy with changes in gene expression in rat dorsal root ganglia (DRG). After 1, 4, or 8 weeks of streptozotocin-induced diabetes, sensory and motor nerve conduction velocities (NCV) were measured as an indicator of neuropathy and changes in gene expression were measured using Affymetrix oligonucleotide microarrays. No significant changes in NCV were found after 1 week of diabetes, but after 4 and 8 weeks, there was a significant reduction in both sensory and motor NCV. Global gene expression changes in diabetic rat DRG were evident from principal component analysis of microarray data after 1, 4, and 8 weeks. Expression changes in individual genes were relatively small in line with a gradual degenerative neuropathy indirectly resulting from diabetes. Sets of differentially expressed genes have been identified and quantitative reverse transcriptase-polymerase chain reaction has been used to confirm the microarray data for several genes. Gene ontology overrepresentation analysis was performed on the microarray data to identify biologic processes altered in diabetic DRG. The genes identified in this study may be responsible for causing the functional deficits and suggest pathways/processes that require further investigation as possible targets for therapeutic intervention.

Antibrain antibodies in children with autism and their unaffected siblings

Serum autoantibodies to human brain, identified by ELISA and Western immunoblotting, were evaluated in 29 children with autism spectrum disorder (22 with autistic disorder), 9 non-autistic siblings and 13 controls. More autistic subjects than controls had bands at 100 kDa in caudate, putamen and prefrontal cortex (p<0.01) as well as larger peak heights of bands at 73 kDa in the cerebellum and cingulate gyrus. Both autistic disorder subjects and their matched non-autistic siblings had denser bands (peak height and/or area under the curve) at 73 kDa in the cerebellum and cingulate gyrus than did controls (p<0.01). Results suggest that children with autistic disorder and their siblings exhibit differences compared to controls in autoimmune reactivity to specific epitopes located in distinct brain regions.

A family based linkage analysis of HLA and 5-HTTLPR gene polymorphisms in Sardinian children with autism spectrum disorder

Autism spectrum disorders (ASD) are characterized by a broad range in clinical presentation. Although a definite genetic cause has not yet been fully demonstrated, family based studies suggest that a multigenic pattern may be responsible for susceptibility, but most results are conflicting and have yet to be replicated. The purpose of this investigation was to analyze the linkage of the human leukocyte antigen (HLA) and the human serotonin transporter coding (5-HTTLPR) genes with ASD in a group of 37 families of Sardinian ethnicity in insular Italy. In 50% of these families, ASD is linked to HLA, and in the other 50% it is linked to 5-HTTLPR polymorphic genes; in other words, linkage to one or the other was evident in all cases. Despite a very homogenous genetic pattern being generally reported for Sardinians, the linkage observed with HLA and 5-HTTLPR genetic regions indicated a statistically defined heterogeneity (p=0.002). No allelic HLA or 5-HTTLPR polymorphisms were specifically associated with ASD, suggesting these loci as markers of other genes mapped in their close proximity that may be more directly involved and thus may merit further analytical studies.

Autism and environmental genomics

Autism spectrum disorders (ASD) are defined by behavior and diagnosed by clinical history and observation but have no biomarkers and are presumably, etiologically and biologically heterogeneous. Given brain abnormalities and high monozygotic concordance, ASDs have been framed as neurobiologically based and highly genetic, which has shaped the research agenda and in particular criteria for choosing candidate ASD genes. Genetic studies to date have not uncovered genes of strong effect, but a move toward "genetic complexity" at the neurobiological level may not suffice, as evidence of systemic abnormalities (e.g. gastrointestinal and immune), increasing rates and less than 100% monozygotic concordance support a more inclusive reframing of autism as a multisystem disorder with genetic influence and environmental contributors. We review this evidence and also use a bioinformatic approach to explore the possibility that "environmentally responsive genes" not specifically associated with the nervous system, but potentially associated with systemic changes in autism, have not hitherto received sufficient attention in autism genetics investigations. We overlapped genes from NIEHS Environmental Genome Project, the Comparative Toxicogenomics Database, and the SeattleSNPs database of genes relevant to the human immune and inflammatory response with linkage regions identified in published autism genome scans. We identified 135 genes in overlap regions, of which 56 had never previously been studied in relation to autism and 47 had functional SNPs (in coding regions). Both our review and the bioinformatics exercise support the expansion of criteria for evaluating the relevance of genes to autism risk to include genes related to systemic impact and environmental responsiveness. This review also suggests the utility of environmental genomic resources in highlighting the potential relevance of particular genes within linkage regions. Environmental responsiveness and systems impacts consistent with system-wide findings in autism are thus supported as important considerations in identifying the numerous and complex modes of gene-environment interaction in autism.

Large-scale mutagenesis and phenotypic screens for the nervous system and behavior in mice

Significant developments have occurred in our understanding of the mammalian genome thanks to informatics, expression profiling and sequencing of the human and rodent genomes. However, although these facets of genomic analysis are being addressed, analysis of in vivo gene function remains a formidable task. Evaluation of the phenotype of mutants provides powerful access to gene function, and this approach is particularly relevant to the nervous system and behavior. Here, we discuss the complementary mouse genetic approaches of gene-driven, targeted mutagenesis and phenotype-driven, chemical mutagenesis. We highlight an NIH-supported large-scale effort to use phenotype-driven mutagenesis screens to identify mouse mutants with neural and behavioral alterations. Such single-gene mutations can then be used for gene identification using positional candidate gene-cloning methods.

Autistic spectrum disorders

Autistic spectrum disorders (ASD), are a group of disorders characterised by qualitative abnormalities in social and emotional behaviour and are associated with restricted, stereotyped and repetitive interests and activities. There has been considerable understanding of ASD in recent years. This educational review paper focuses on four areas of interest and relevance to trainees preparing for the membership examination of the Royal College of Psychiatrists (MRCPsych): (a) diagnosing ASD; (b) epidemiology of ASD; (c) aetiology, including genetic, cognitive and neurochemical/neuropathological theories in ASD; and (d) treatment of ASD. Relevant papers are discussed and recommendations for further reading are provided.

The Autism Genome Project: goals and strategies

Autism is a complex neurodevelopmental disorder with a broad spectrum of symptoms and varying severity. Currently, no biological diagnosis exists. Although there has been a significant increase in autism genetics research recently, validated susceptibility genes for the most common, sporadic forms of autistic disorder, as well as familial autism, have yet to be identified. The identification of autism-susceptibility genes will not only assist in the identification and/or development of better medications that can help improve the health and neurodevelopment of children with autism, but will also allow for better perinatal diagnosis. The Autism Genome Project (AGP) is a large-scale, collaborative genetics research project initiated by the National Alliance for Autism Research and the National Institutes of Health, and is aimed at sifting through the human genome in search of autism-susceptibility genes. Phase I of the AGP will consist of genome-wide scans utilizing both SNP array and microsatellite technologies. Linkage analysis will subsequently be performed on approximately 1500 pedigrees as will downstream fine-mapping and sequencing of the critical linkage intervals. Ultimately, the vision will be to identify the exact nucleotide variants within genes which give rise to predisposition. The AGP intends to move the field of autism clinical management forward by answering questions about the causal mechanisms underlying the pathophysiology of autism. From this knowledge, therapeutic targets for drug treatments, and ultimately, a newborn screening diagnostic that would allow for early intervention, can begin to be developed.