Genetics evaluation for the etiologic diagnosis of autism spectrum disorders

Metabolic pathology of autism in relation to redox metabolism

An imbalance in glutathione-dependent redox metabolism has been shown to be associated with autism spectrum disorder (ASD). Glutathione synthesis and intracellular redox balance are linked to folate and methylation metabolism, metabolic pathways that have also been shown to be abnormal in ASD. Together, these metabolic abnormalities define a distinct ASD endophenotype that is closely associated with genetic, epigenetic and mitochondrial abnormalities, as well as environmental factors related to ASD. Biomarkers that reflect these metabolic abnormalities will be discussed in the context of an ASD metabolic endophenotype that may lead to a better understanding of the pathophysiological mechanisms underlying core and associated ASD symptoms. Last, we discuss how these biomarkers have been used to guide the development of novel ASD treatments.

Fragile X spectrum disorders

The fragile X mental retardation 1 gene (FMR1), which codes for the fragile X mental retardation 1 protein (FMRP), is located at Xp27.3. The normal allele of the FMR1 gene typically has 5 to 40 CGG repeats in the 5' untranslated region; abnormal alleles of dynamic mutations include the full mutation (> 200 CGG repeats), premutation (55-200 CGG repeats) and the gray zone mutation (45-54 CGG repeats). Premutation carriers are common in the general population with approximately 1 in 130-250 females and 1 in 250-810 males, whereas the full mutation and Fragile X syndrome (FXS) occur in approximately 1 in 4000 to 1 in 7000. FMR1 mutations account for a variety of phenotypes including the most common monogenetic cause of inherited intellectual disability (ID) and autism (FXS), the most common genetic form of ovarian failure, the fragile X-associated primary ovarian insufficiency (FXPOI, premutation); and fragile X-associated tremor/ataxia syndrome (FXTAS, premutation). The premutation can also cause developmental problems including ASD and ADHD especially in boys and psychopathology including anxiety and depression in children and adults. Some premutation carriers can have a deficit of FMRP and some unmethylated full mutation individuals can have elevated FMR1 mRNA that is considered a premutation problem. Therefore the term "Fragile X Spectrum Disorder" (FXSD) should be used to include the wide range of overlapping phenotypes observed in affected individuals with FMR1 mutations. In this review we focus on the phenotypes and genotypes of children with FXSD.

Treatments for biomedical abnormalities associated with autism spectrum disorder

Recent studies point to the effectiveness of novel treatments that address physiological abnormalities associated with autism spectrum disorder (ASD). This is significant because safe and effective treatments for ASD remain limited. These physiological abnormalities as well as studies addressing treatments of these abnormalities are reviewed in this article. Treatments commonly used to treat mitochondrial disease have been found to improve both core and associated ASD symptoms. Double-blind, placebo-controlled (DBPC) studies have investigated l-carnitine and a multivitamin containing B vitamins, antioxidants, vitamin E, and co-enzyme Q10 while non-blinded studies have investigated ubiquinol. Controlled and uncontrolled studies using folinic acid, a reduced form of folate, have reported marked improvements in core and associated ASD symptoms in some children with ASD and folate related pathway abnormities. Treatments that could address redox metabolism abnormalities include methylcobalamin with and without folinic acid in open-label studies and vitamin C and N-acetyl-l-cysteine in DBPC studies. These studies have reported improved core and associated ASD symptoms with these treatments. Lastly, both open-label and DBPC studies have reported improvements in core and associated ASD symptoms with tetrahydrobiopterin. Overall, these treatments were generally well-tolerated without significant adverse effects for most children, although we review the reported adverse effects in detail. This review provides evidence for potentially safe and effective treatments for core and associated symptoms of ASD that target underlying known physiological abnormalities associated with ASD. Further research is needed to define subgroups of children with ASD in which these treatments may be most effective as well as confirm their efficacy in DBPC, large-scale multicenter studies.

Uptake and Diagnostic Yield of Chromosomal Microarray in an Australian Child Development Clinic

Autism is an etiologically heterogeneous developmental disorder for which the range of genetic investigations has expanded considerably over the past decade. Introduction of chromosomal microarray (CMA) to clinical practice has expanded the range of conditions which pediatricians are able to detect. This study reviewed the utilization, yield and cost of genetic investigations in a sample of children with pervasive developmental disorders (PDD) in an Australian metropolitan child development service. Six hundred and ninety eight patients with PDD were identified from the clinic population. One hundred and ten (15.7%) of the clinic population had undergone investigation with chromosomal microarray, 140 (20.0%) with karyotype (KT), and 167 (23.9%) with Fragile X testing (FRGX). Twelve (10.9%) CMA findings were reported, of which seven (6.3%) were felt to be the likely cause of the child’s clinical features. Five (3.5%) KT findings were reported, of which four (2.9%) were felt to be the likely cause of the child’s clinical features. Two patients (1.2%) were identified with Fragile X expansions. One fifth of the clinic’s recent PDD population had undergone testing with CMA. CMA appears to have increased the diagnostic yield of the genetic investigation of autism, in line with internationally reported levels. Number needed to test (NNT) and cost per incremental diagnosis, were also in line with internationally reported levels.

Sleep, plasticity and the pathophysiology of neurodevelopmental disorders: the potential roles of protein synthesis and other cellular processes

Sleep is important for neural plasticity, and plasticity underlies sleep-dependent memory consolidation. It is widely appreciated that protein synthesis plays an essential role in neural plasticity. Studies of sleep-dependent memory and sleep-dependent plasticity have begun to examine alterations in these functions in populations with neurological and psychiatric disorders. Such an approach acknowledges that disordered sleep may have functional consequences during wakefulness. Although neurodevelopmental disorders are not considered to be sleep disorders per se, recent data has revealed that sleep abnormalities are among the most prevalent and common symptoms and may contribute to the progression of these disorders. The main goal of this review is to highlight the role of disordered sleep in the pathology of neurodevelopmental disorders and to examine some potential mechanisms by which sleep-dependent plasticity may be altered. We will also briefly attempt to extend the same logic to the other end of the developmental spectrum and describe a potential role of disordered sleep in the pathology of neurodegenerative diseases. We conclude by discussing ongoing studies that might provide a more integrative approach to the study of sleep, plasticity, and neurodevelopmental disorders.

Practice parameter for the assessment and treatment of children and adolescents with autism spectrum disorder

Autism spectrum disorder is characterized by patterns of delay and deviance in the development of social, communicative, and cognitive skills that arise in the first years of life. Although frequently associated with intellectual disability, this condition is distinctive in its course, impact, and treatment. Autism spectrum disorder has a wide range of syndrome expression and its management presents particular challenges for clinicians. Individuals with an autism spectrum disorder can present for clinical care at any point in development. The multiple developmental and behavioral problems associated with this condition necessitate multidisciplinary care, coordination of services, and advocacy for individuals and their families. Early, sustained intervention and the use of multiple treatment modalities are indicated.

Disentangling the heterogeneity of autism spectrum disorder through genetic findings

Autism spectrum disorder (ASD) represents a heterogeneous group of disorders, which presents a substantial challenge to diagnosis and treatment. Over the past decade, considerable progress has been made in the identification of genetic risk factors for ASD that define specific mechanisms and pathways underlying the associated behavioural deficits. In this Review, we discuss how some of the latest advances in the genetics of ASD have facilitated parsing of the phenotypic heterogeneity of this disorder. We argue that only through such advances will we begin to define endophenotypes that can benefit from targeted, hypothesis-driven treatments. We review the latest technologies used to identify and characterize the genetics underlying ASD and then consider three themes-single-gene disorders, the gender bias in ASD, and the genetics of neurological comorbidities-that highlight ways in which we can use genetics to define the many phenotypes within the autism spectrum. We also present current clinical guidelines for genetic testing in ASD and their implications for prognosis and treatment.

The contribution of epigenetics to understanding genetic factors in autism

Autism spectrum disorder is a grouping of neurodevelopmental disorders characterized by deficits in social communication and language, as well as by repetitive and stereotyped behaviors. While the environment is believed to play a role in the development of autism spectrum disorder, there is now strong evidence for a genetic link to autism. Despite such evidence, studies investigating a potential single-gene cause for autism, although insightful, have been highly inconclusive. A consideration of an epigenetic approach proves to be very promising in clarifying genetic factors involved in autism. The present article is intended to provide a review of key findings pertaining to epigenetics in autism in such a way that a broader audience of individuals who do not have a strong background in genetics may better understand this highly specific and scientific content. Epigenetics refers to non-permanent heritable changes that alter expression of genes without altering the DNA sequence itself and considers the role of environment in this modulation of gene expression. This review provides a brief description of epigenetic processes, highlights evidence in the literature of epigenetic dysregulation in autism, and makes use of noteworthy findings to illustrate how a consideration of epigenetic factors can deepen our understanding of the development of autism. Furthermore, this discussion will present a promising new way for moving forward in the investigation of genetic factors within autism.

Genetic testing and genetic counseling among Medicaid-enrolled children with autism spectrum disorder in 2001 and 2007

The rise in the prevalence of autism spectrum disorder (ASD) has resulted in increased efforts to understand the causes of this complex set of disorders that emerge early in childhood. Although research in this area is underway and yielding useful, but complex information about ASD, guidelines for the use of genetic testing and counseling among children with ASD conflict. The purpose of this study was to determine the frequency of use of genetic testing and counseling before the widespread implementation of clinical chromosomal microarray (CMA) to establish a baseline for the use of both services and to investigate potential disparities in the use of both services among children with ASD. We found that about two-thirds of children with ASD received genetic testing or counseling and the use of both services is increasing with time, even in the pre-CMA era. Being female and having a comorbid intellectual disability diagnosis both increased the likelihood of receiving genetic testing and genetic counseling. Initial discrepancies in the use of both services based on race/ethnicity suggest that troubling disparities observed in other services delivered to children with ASD and other mental health disorders persist in genetic testing and counseling as well. These results should incentivize further investigation of the impact of genetic testing and counseling on children with ASD and their families, and should drive efforts to explore and confront disparities in the delivery of these services, particularly with the advancing scientific research on this topic.

Effects of stimulus salience on touchscreen serial reversal learning in a mouse model of fragile X syndrome

Fragile X syndrome (FXS) is the most common inherited form of intellectual disability in males and the most common genetic cause of autism. Although executive dysfunction is consistently found in humans with FXS, evidence of executive dysfunction in Fmr1 KO mice, a mouse model of FXS, has been inconsistent. One possible explanation for this is that executive dysfunction in Fmr1 KO mice, similar to humans with FXS, is only evident when cognitive demands are high. Using touchscreen operant conditioning chambers, male Fmr1 KO mice and their male wildtype littermates were tested on the acquisition of a pairwise visual discrimination followed by four serial reversals of the response rule. We assessed reversal learning performance under two different conditions. In the first, the correct stimulus was salient and the incorrect stimulus was non-salient. In the second and more challenging condition, the incorrect stimulus was salient and the correct stimulus was non-salient; this increased cognitive load by introducing conflict between sensory-driven (i.e., bottom-up) and task-dependent (i.e., top-down) signals. Fmr1 KOs displayed two distinct impairments relative to wildtype littermates. First, Fmr1 KOs committed significantly more learning-type errors during the second reversal stage, but only under high cognitive load. Second, during the first reversal stage, Fmr1 KOs committed significantly more attempts to collect a reward during the timeout following an incorrect response. These findings indicate that Fmr1 KO mice display executive dysfunction that, in some cases, is only evident under high cognitive load.

Autism spectrum disorders: the quest for genetic syndromes

Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disabilities with various etiologies, but with a heritability estimate of more than 90%. Although the strong correlation between autism and genetic factors has been long established, the exact genetic background of ASD remains unclear. A number of genetic syndromes manifest ASD at higher than expected frequencies compared to the general population. These syndromes account for more than 10% of all ASD cases and include tuberous sclerosis, fragile X, Down, neurofibromatosis, Angelman, Prader-Willi, Williams, Duchenne, etc. Clinicians are increasingly required to recognize genetic disorders in individuals with ASD, in terms of providing proper care and prognosis to the patient, as well as genetic counseling to the family. Vice versa, it is equally essential to identify ASD in patients with genetic syndromes, in order to ensure correct management and appropriate educational placement. During investigation of genetic syndromes, a number of issues emerge: impact of intellectual disability in ASD diagnoses, identification of autistic subphenotypes and differences from idiopathic autism, validity of assessment tools designed for idiopathic autism, possible mechanisms for the association with ASD, etc. Findings from the study of genetic syndromes are incorporated into the ongoing research on autism etiology and pathogenesis; different syndromes converge upon common biological backgrounds (such as disrupted molecular pathways and brain circuitries), which probably account for their comorbidity with autism. This review paper critically examines the prevalence and characteristics of the main genetic syndromes, as well as the possible mechanisms for their association with ASD.

Clinical genetics evaluation in identifying the etiology of autism spectrum disorders: 2013 guideline revisions

The autism spectrum disorders are a collective of conditions that have in common impaired socialization and communication in association with stereotypic behaviors. The reported incidence of autism spectrum disorders has increased dramatically over the past two decades. In addition, increased attention has been paid to these conditions by both lay and professional groups. These trends have resulted in an increase in the number of referrals to clinical geneticist for the evaluation of persons with autism spectrum disorders. The primary roles of the geneticist in this process are to define etiology when possible, to provide genetic counseling, and to contribute to case management. In deciding on the appropriate evaluation for a particular patient, the geneticist will consider a host of factors: (i) ensuring an accurate diagnosis of autism before proceeding with any investigation; (ii) discussing testing options, diagnostic yields, and family investment before proceeding with an evaluation; (iii) communicating and coordinating with the patient-centered medical home (PCMH); (iv) assessing the continuously expanding and evolving list of available laboratory-testing modalities in light of the published literature; (v) recognizing the expanded phenotypes of well-described syndromic and metabolic conditions that overlap with autism spectrum disorders; and (vi) defining an individualized evaluation plan based on the unique history and clinical features of a given patient. The guidelines in this paper have been developed to assist the clinician in the consideration of these factors. It updates the original publication from 2008.Genet Med 2013:15(5):399-407.

Metabolic effects of sapropterin treatment in autism spectrum disorder: a preliminary study

Sapropterin, a synthetic form of tetrahydrobiopterin (BH4), has been reported to improve symptoms in children with autism spectrum disorder (ASD). However, as BH4 is involved in multiple metabolic pathway that have been found to be dysregulated in ASD, including redox, pterin, monoamine neurotransmitter, nitric oxide (NO) and immune metabolism, the metabolic pathway by which sapropterin exerts its therapeutic effect in ASD effect remains unclear. This study investigated which metabolic pathways were associated with symptomatic improvement during sapropterin treatment. Ten participants (ages 2-6 years old) with current social and/or language delays, ASD and a central BH4 concentration 30 nM l(-1) were treated with a daily morning 20 mg kg(-1) dose of sapropterin for 16 weeks in an open-label fashion. At baseline, 8 weeks and 16 weeks after starting the treatment, measures of language, social function and behavior and biomarkers of redox, pterin, monoamine neurotransmitter, NO and immune metabolism were obtained. Two participants discontinued the study, one from mild adverse effects and another due to noncompliance. Overall, improvements in subscales of the Preschool Language Scale (PLS), Vineland Adaptive Behavior Scale (VABS), Aberrant Behavior Checklist (ABC) and autism symptoms questionnaire (ASQ) were seen. Significant changes in biomarkers of pterin, redox and NO were found. Improvement on several subscales of the PLS, VABS, ABC and ASQ were moderated by baseline and changes in biomarkers of NO and pterin metabolism, particularly baseline NO metabolism. These data suggest that behavioral improvement associated with daily 20 mg kg(-1) sapropterin treatment may involve NO metabolism, particularly the status of pretreatment NO metabolism.

Autism spectrum disorder in the genetics clinic: a review

Autism spectrum disorders (ASDs) are a heterogeneous group of neurodevelopmental disorders affecting social communication, language and behavior. The underlying cause(s) in a given individual is often elusive, with the exception of clinically recognizable genetic syndromes with readily available molecular diagnosis, such as fragile X syndrome. Clinical geneticists approach patients with ASDs by ruling out known genetic and genomic syndromes, leaving more than 80% of families without a definitive diagnosis and an uncertain risk of recurrence. Advances in microarray technology and next-generation sequencing are revealing rare variants in genes with important roles in synapse formation, function and maintenance. This review will focus on the clinical approach to ASDs, given the current state of knowledge about their complex genetic architecture.

Fragile X syndrome: from targets to treatments

Fragile X syndrome (FXS) is one of the most prevalent and well-studied monogenetic causes of intellectual disability and autism and, although rare, its high penetrance makes it a desirable model for the study of neurodevelopmental disorders more generally. Indeed recent studies suggest that there is functional convergence of a number of genes that are implicated in intellectual disability and autism indicating that an understanding of the cellular and biochemical dysfunction that occurs in monogenic forms of these disorders are likely to reveal common targets for therapeutic intervention. Fundamental research into FXS has provided a wealth of information about how the loss of function of the fragile X mental retardation protein results in biochemical, anatomical and physiological dysfunction leading to the discovery of interventions that correct many of the core pathological phenotypes associated with animal models of FXS. Most promisingly such strategies have led to development of drugs that are now in clinical trials. This review highlights how progress in understanding disorders such as FXS has led to a new era in which targeted molecular treatment towards neurodevelopmental disorders is becoming a reality. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.

Hyperbaric oxygen treatment in autism spectrum disorders

Traditionally, hyperbaric oxygen treatment (HBOT) is indicated in several clinical disorders include decompression sickness, healing of problem wounds and arterial gas embolism. However, some investigators have used HBOT to treat individuals with autism spectrum disorders (ASD). A number of individuals with ASD possess certain physiological abnormalities that HBOT might ameliorate, including cerebral hypoperfusion, inflammation, mitochondrial dysfunction and oxidative stress. Studies of children with ASD have found positive changes in physiology and/or behavior from HBOT. For example, several studies have reported that HBOT improved cerebral perfusion, decreased markers of inflammation and did not worsen oxidative stress markers in children with ASD. Most studies of HBOT in children with ASD examined changes in behaviors and reported improvements in several behavioral domains although many of these studies were not controlled. Although the two trials employing a control group reported conflicting results, a recent systematic review noted several important distinctions between these trials. In the reviewed studies, HBOT had minimal adverse effects and was well tolerated. Studies which used a higher frequency of HBOT sessions (e.g., 10 sessions per week as opposed to 5 sessions per week) generally reported more significant improvements. Many of the studies had limitations which may have contributed to inconsistent findings across studies, including the use of many different standardized and non-standardized instruments, making it difficult to directly compare the results of studies or to know if there are specific areas of behavior in which HBOT is most effective. The variability in results between studies could also have been due to certain subgroups of children with ASD responding differently to HBOT. Most of the reviewed studies relied on changes in behavioral measurements, which may lag behind physiological changes. Additional studies enrolling children with ASD who have certain physiological abnormalities (such as inflammation, cerebral hypoperfusion, and mitochondrial dysfunction) and which measure changes in these physiological parameters would be helpful in further defining the effects of HBOT in ASD.

A review of research trends in physiological abnormalities in autism spectrum disorders: immune dysregulation, inflammation, oxidative stress, mitochondrial dysfunction and environmental toxicant exposures

Recent studies have implicated physiological and metabolic abnormalities in autism spectrum disorders (ASD) and other psychiatric disorders, particularly immune dysregulation or inflammation, oxidative stress, mitochondrial dysfunction and environmental toxicant exposures ('four major areas'). The aim of this study was to determine trends in the literature on these topics with respect to ASD. A comprehensive literature search from 1971 to 2010 was performed in these four major areas in ASD with three objectives. First, publications were divided by several criteria, including whether or not they implicated an association between the physiological abnormality and ASD. A large percentage of publications implicated an association between ASD and immune dysregulation/inflammation (416 out of 437 publications, 95%), oxidative stress (all 115), mitochondrial dysfunction (145 of 153, 95%) and toxicant exposures (170 of 190, 89%). Second, the strength of evidence for publications in each area was computed using a validated scale. The strongest evidence was for immune dysregulation/inflammation and oxidative stress, followed by toxicant exposures and mitochondrial dysfunction. In all areas, at least 45% of the publications were rated as providing strong evidence for an association between the physiological abnormalities and ASD. Third, the time trends in the four major areas were compared with trends in neuroimaging, neuropathology, theory of mind and genetics ('four comparison areas'). The number of publications per 5-year block in all eight areas was calculated in order to identify significant changes in trends. Prior to 1986, only 12 publications were identified in the four major areas and 51 in the four comparison areas (42 for genetics). For each 5-year period, the total number of publications in the eight combined areas increased progressively. Most publications (552 of 895, 62%) in the four major areas were published in the last 5 years (2006-2010). Evaluation of trends between the four major areas and the four comparison areas demonstrated that the largest relative growth was in immune dysregulation/inflammation, oxidative stress, toxicant exposures, genetics and neuroimaging. Research on mitochondrial dysfunction started growing in the last 5 years. Theory of mind and neuropathology research has declined in recent years. Although most publications implicated an association between the four major areas and ASD, publication bias may have led to an overestimation of this association. Further research into these physiological areas may provide insight into general or subset-specific processes that could contribute to the development of ASD and other psychiatric disorders.

Phosphatase and tensin homolog (PTEN) gene mutations and autism: literature review and a case report of a patient with Cowden syndrome, autistic disorder, and epilepsy

Phosphatase and tensin homolog (PTEN) gene mutations are associated with a spectrum of clinical disorders characterized by skin lesions, macrocephaly, hamartomatous overgrowth of tissues, and an increased risk of cancers. Autism has rarely been described in association with these variable clinical features. At present, 24 patients with phosphatase and tensin homolog gene mutation, autism, macrocephaly, and some clinical findings described in phosphatase and tensin homolog syndromes have been reported in the literature. We describe a 14-year-old boy with autistic disorder, focal epilepsy, severe and progressive macrocephaly, and multiple papular skin lesions and palmoplantar punctate keratoses, characteristic of Cowden syndrome. The boy has a de novo phosphatase and tensin homolog gene mutation. Our patient is the first case described to present a typical Cowden syndrome and autism associated with epilepsy.

Facial phenotypes in subgroups of prepubertal boys with autism spectrum disorders are correlated with clinical phenotypes

BACKGROUND

The brain develops in concert and in coordination with the developing facial tissues, with each influencing the development of the other and sharing genetic signaling pathways. Autism spectrum disorders (ASDs) result from alterations in the embryological brain, suggesting that the development of the faces of children with ASD may result in subtle facial differences compared to typically developing children. In this study, we tested two hypotheses. First, we asked whether children with ASD display a subtle but distinct facial phenotype compared to typically developing children. Second, we sought to determine whether there are subgroups of facial phenotypes within the population of children with ASD that denote biologically discrete subgroups.

METHODS

The 3dMD cranial System was used to acquire three-dimensional stereophotogrammetric images for our study sample of 8- to 12-year-old boys diagnosed with essential ASD (n = 65) and typically developing boys (n = 41) following approved Institutional Review Board protocols. Three-dimensional coordinates were recorded for 17 facial anthropometric landmarks using the 3dMD Patient software. Statistical comparisons of facial phenotypes were completed using Euclidean Distance Matrix Analysis and Principal Coordinates Analysis. Data representing clinical and behavioral traits were statistically compared among groups by using χ2 tests, Fisher's exact tests, Kolmogorov-Smirnov tests and Student's t-tests where appropriate.

RESULTS

First, we found that there are significant differences in facial morphology in boys with ASD compared to typically developing boys. Second, we also found two subgroups of boys with ASD with facial morphology that differed from the majority of the boys with ASD and the typically developing boys. Furthermore, membership in each of these distinct subgroups was correlated with particular clinical and behavioral traits.

CONCLUSIONS

Boys with ASD display a facial phenotype distinct from that of typically developing boys, which may reflect alterations in the prenatal development of the brain. Subgroups of boys with ASD defined by distinct facial morphologies correlated with clinical and behavioral traits, suggesting potentially different etiologies and genetic differences compared to the larger group of boys with ASD. Further investigations into genes involved in neurodevelopment and craniofacial development of these subgroups will help to elucidate the causes and significance of these subtle facial differences.

Mycobacterium paratuberculosis and autism: is this a trigger?

Autism is a heterogeneous group of life-long neurologic problems that begin in childhood. Success in efforts to understand and treat autism has been mostly elusive. The role of autoimmunity in autism has gained recognition both for associated systemic autoimmune disease and the presence of brain autoantibodies in autistic children and their family members. There is an acknowledged genetic susceptibility to autism--most notably allotypes of complement C4. C4 defects are associated with several autoimmune diseases and also confer susceptibility to mycobacterial infections. Mycobacterium avium ss. paratuberculosis (MAP) causes an enteric inflammatory disease in ruminant animals (Johne's disease) and is the putative cause of the very similar Crohn's disease in humans. Humans are widely exposed to MAP in food and water. MAP has been also linked to ulcerative colitis, irritable bowel syndrome, sarcoidosis, Blau syndrome, autoimmune (Type 1) diabetes, Hashimoto's thyroiditis and multiple sclerosis. Environmental agents are thought to trigger autism in the genetically at risk. Molecular mimicry is the proposed mechanism by which MAP is thought to trigger autoantibodies. Autoantibodies to brain myelin basic protein (MBP) is a common feature of autism. This article considers the subset of autoimmunity-related autism patients and postulates that MAP, through molecular mimicry to its heat shock protein HSP65, triggers autism by stimulating antibodies that cross react with myelin basic protein (MBP).

What can we learn about autism from studying fragile X syndrome?

Despite early controversy, it is now accepted that a substantial proportion of children with fragile X syndrome (FXS) meets diagnostic criteria for autism spectrum disorder (ASD). This change has led to an increased interest in studying the association of FXS and ASD because of the clinical consequences of their co-occurrence and the implications for a better understanding of ASD in the general population. Here, we review the current knowledge on the behavioral, neurobiological (i.e., neuroimaging), and molecular features of ASD in FXS, as well as the insight into ASD gained from mouse models of FXS. This review covers critical issues such as the selectivity of ASD in disorders associated with intellectual disability, differences between autistic features and ASD diagnosis, and the relationship between ASD and anxiety in FXS patients and animal models. While solid evidence supporting ASD in FXS as a distinctive entity is emerging, neurobiological and molecular data are still scarce. Animal model studies have not been particularly revealing about ASD in FXS either. Nevertheless, recent studies provide intriguing new leads and suggest that a better understanding of the bases of ASD will require the integration of multidisciplinary data from FXS and other genetic disorders.

Traditional and non-traditional treatments for autism spectrum disorder with seizures: an on-line survey

BACKGROUND

Despite the high prevalence of seizure, epilepsy and abnormal electroencephalograms in individuals with autism spectrum disorder (ASD), there is little information regarding the relative effectiveness of treatments for seizures in the ASD population. In order to determine the effectiveness of traditional and non-traditional treatments for improving seizures and influencing other clinical factor relevant to ASD, we developed a comprehensive on-line seizure survey.

METHODS

Announcements (by email and websites) by ASD support groups asked parents of children with ASD to complete the on-line surveys. Survey responders choose one of two surveys to complete: a survey about treatments for individuals with ASD and clinical or subclinical seizures or abnormal electroencephalograms, or a control survey for individuals with ASD without clinical or subclinical seizures or abnormal electroencephalograms. Survey responders rated the perceived effect of traditional antiepileptic drug (AED), non-AED seizure treatments and non-traditional ASD treatments on seizures and other clinical factors (sleep, communication, behavior, attention and mood), and listed up to three treatment side effects.

RESULTS

Responses were obtained concerning 733 children with seizures and 290 controls. In general, AEDs were perceived to improve seizures but worsened other clinical factors for children with clinical seizure. Valproic acid, lamotrigine, levetiracetam and ethosuximide were perceived to improve seizures the most and worsen other clinical factors the least out of all AEDs in children with clinical seizures. Traditional non-AED seizure and non-traditional treatments, as a group, were perceived to improve other clinical factors and seizures but the perceived improvement in seizures was significantly less than that reported for AEDs. Certain traditional non-AED treatments, particularly the ketogenic diet, were perceived to improve both seizures and other clinical factors.For ASD individuals with reported subclinical seizures, other clinical factors were reported to be worsened by AEDs and improved by non-AED traditional seizure and non-traditional treatments. The rate of side effects was reportedly higher for AEDs compared to traditional non-AED treatments.

CONCLUSION

Although this survey-based method only provides information regarding parental perceptions of effectiveness, this information may be helpful for selecting seizure treatments in individuals with ASD.

How to communicate with vaccine-hesitant parents

Development of safe and effective vaccines is one the greatest medical triumphs. However, despite high immunization rates in the United States, 85% of health care providers (HCPs) will have a parent refuse a vaccine for his or her child each year. HCPs have the greatest influence on a parent's decision to vaccinate his or her child. To effectively communicate with vaccine-hesitant parents, HCPs must first understand the concerns of parents regarding immunization and understand influences that can lead to misinformation about the safety and effectiveness of vaccines. HCPs should establish an open, nonconfrontational dialogue with vaccine-hesitant parents at an early stage and provide unambiguous, easily comprehensible answers about known vaccine adverse events and provide accurate information about vaccination. Personal stories and visual images of patients and parents affected by vaccine-preventable diseases and reports of disease outbreaks serve as useful reminders of the need to maintain high immunization rates. Ongoing dialogue including provider recommendations may successfully reassure vaccine-hesitant parents that immunization is the best and safest option for their child.

Mitochondrial dysfunction can connect the diverse medical symptoms associated with autism spectrum disorders

Autism spectrum disorder (ASD) is a devastating neurodevelopmental disorder. Over the past decade, evidence has emerged that some children with ASD suffer from undiagnosed comorbid medical conditions. One of the medical disorders that has been consistently associated with ASD is mitochondrial dysfunction. Individuals with mitochondrial disorders without concomitant ASD manifest dysfunction in multiple high-energy organ systems, such as the central nervous, muscular, and gastrointestinal (GI) systems. Interestingly, these are the identical organ systems affected in a significant number of children with ASD. This finding increases the possibility that mitochondrial dysfunction may be one of the keys that explains the many diverse symptoms observed in some children with ASD. This article will review the importance of mitochondria in human health and disease, the evidence for mitochondrial dysfunction in ASD, the potential role of mitochondrial dysfunction in the comorbid medical conditions associated with ASD, and how mitochondrial dysfunction can bridge the gap for understanding how these seemingly disparate medical conditions are related. We also review the limitations of this evidence and other possible explanations for these findings. This new understanding of ASD should provide researchers a pathway for understanding the etiopathogenesis of ASD and clinicians the potential to develop medical therapies.

Genomic designation: how genetics can delineate new, phenotypically diffuse medical categories

This paper reports and discusses 'genomic designation' as a way of classifying people. In genomic designation the object of biomedical analysis--and the concomitant medical category that is subject to scientific, clinical, and social action--is delineated on a genomic basis, while the phenotype is decentralized and tabulated post factum. Unlike prominent sociological concepts such as biosociality or geneticization, where genetic proclivities for or explanations of phenotypic categories affect social processes, genomic designation treats characteristics of the genome as the essential referent of new categories of illness. I outline the relevant sociological literature and the shift to what Nikolas Rose has called the 'molecular gaze' before explicating the concept ofgenomic designation and its half-century history. I use 22q13 Deletion/Phelan-McDermid syndrome as an example of genomic designation: investigations into the deletion of genetic material at site q13 on the 22nd chromosome preceded and made practicable the delineation of a syndrome more than a decade later, even though the associated phenotype is not distinct enough for diagnosis. Finally, I discuss the implications of this turn to 'rigidly designate' kinds of people according to observations made at the level of the genome and outline directions for future research.

The Genetics of Autism

This chapter is written to make the fast-paced, expanding field of the genetics of autism accessible to those practitioners who help children with autism. New genetic knowledge and technology have quickly developed over the past 30 years, particularly within the past decade, and have made many optimistic about our ability to explain autism. Among these advances include the sequencing of the human genome (Lander et al., 2001) and the identification of common genetic variants via the HapMap project (International HapMap Consortium, 2005), and the development of cost-efficient genotyping and analysis technologies (Losh, Sullivan, Trembath, & Piven, 2008). Improvement in technology has led to improved visualization of chromosomal abnormality down to the molecular level. The four most common syndromes associated with autism include fragile X syndrome, tuberous sclerosis, 15q duplications, and untreated phenylketonuria (PKU; Costa e Silva, 2008). FXS and 15q duplications are discussed within the context of cytogenetics. TSC is illustrated within the description of linkage analysis.

Epilepsy and EEG paroxysmal abnormalities in autism spectrum disorders

The occurrence of epilepsy in autism is variable; nevertheless, EEG paroxysmal abnormalities (PA) are frequently recorded in patients with autism, although the influence of epilepsy and/or EEG PA on the autistic regression has not been clarified yet. We examine a large sample of 345 inpatients with autism, divided into three groups: (1) patients without epilepsy and EEG PA; (2) patients with EEG PA but no seizures; (3) patients with epilepsy including febrile convulsions. The prevalence of epilepsy (24.9%) and EEG PA (45.5%) was higher than that reported in the general population. The significant differences among the three groups concerned autistic regression (comparison between groups 1 and 2, p<0.05; comparison between groups 1 and 3, p<0.01), cerebral lesions (comparison between groups 1 and 2, p<0.05; between groups 1 and 3, p<0.001), and symptomatic autism (comparison between groups 1 and 2 as much as comparison between groups 1 and 3, p<0.001), which were prevalent in groups 2 and 3; while severe/profound mental retardation was more frequent in group 3 compared to group 1 (p<0.01). Focal epilepsy (43.0%) and febrile convulsions (33.7%) were frequent in the third group with epilepsy. EEG PA were mainly localized in temporal and central areas (31.4%). Only 2.6% of patients had subcontinuous/continuous EEG PA during sleep. Seizures and EEG PA were not related to autistic regression. EEG PA occurred mainly in childhood, while epilepsy tended to occur (p<0.001) as age increased. The age at onset of seizures had two peaks: between 0 and 5 and between 10 and 15 years with no difference between idiopathic and symptomatic cases. In 58.5% of subjects aged > or = 20 years, epilepsy including febrile seizures occurred at some point of their lives, while cases with only EEG PA were less frequent (9.7%). The relationship among autism, EEG PA and epilepsy should be clarified and investigated. In autism, seizures and EEG PA could represent an epiphenomenon of a cerebral dysfunction independent of apparent lesions.

Cognitive and behavioral characterization of 16p11.2 deletion syndrome

OBJECTIVE

To describe cognitive and behavioral features of patients with chromosome 16p11.2 deletion syndrome, a recently identified and common genetic cause of neurodevelopmental disability, especially autism spectrum disorder (ASD).

METHOD

Twenty-one patients with 16p11.2 deletion were evaluated by medical record review. A subset of 11 patients consented to detailed cognitive, behavioral, and autism diagnostic assessment.

RESULTS

Patients with 16p11.2 deletion had varying levels of intellectual disability, variable adaptive skills, and a high incidence of language delay. Attention issues were not as frequent as had been reported in previous clinical reports. Atypical language, reduced social skills, and maladaptive behaviors were common, as was diagnosis of ASD. Based on medical record review, 7 of 21 patients (33%) had an ASD diagnosis. Among patients receiving detailed phenotyping, 3 of 11 (27%) met full criteria (met cutoff scores on both Autism Diagnostic Observation Schedule and Autism Diagnostic Interview) for an ASD diagnosis, whereas 6 other patients (55%) met criteria for ASD on either the Autism Diagnostic Observation Schedule or the Autism Diagnostic Interview, but not both measures.

CONCLUSIONS

Rates of ASD were similar to previous reports that are based on medical record reviews, but formal assessment revealed that a majority of patients with 16p11.2 deletion demonstrate features of ASD beyond simple language impairment. All patients with 16p11.2 deletion should receive formal neurodevelopmental evaluation including measures to specifically assess cognitive, adaptive, language, and psychiatric/behavioral issues. Clinical evaluation of this patient population should always include assessment by Autism Diagnostic Interview and Autism Diagnostic Observation Schedule to detect behaviors related to ASD and possible ASD diagnosis.

Pre-eclampsia, birth weight, and autism spectrum disorders

Autism spectrum disorders (ASD) are primarily inherited, but perinatal or other environmental factors may also be important. In an analysis of 87,677 births from 1996 through 2002, insured by the South Carolina Medicaid program, birth weight was significantly inversely associated with the odds of ASD (OR = 0.78, p = .001 for each additional kilogram). Maternal pre-eclampsia/eclampsia was significantly associated with greater odds of ASD (OR = 1.85, p < .0001 without controlling for birth weight; OR = 1.69, p = .0005, when controlling for birth weight). We conclude that reduced birth weight partially mediates the association between pre-eclampsia/eclampsia and ASD. Additional research is needed to investigate the potential mechanism(s) by which pre-eclampsia/eclampsia may influence ASD risk.

Autism spectrum disorders and epigenetics

OBJECTIVE

Current research suggests that the causes of autism spectrum disorders (ASD) are multifactorial and include both genetic and environmental factors. Several lines of evidence suggest that epigenetics also plays an important role in ASD etiology and that it might, in fact, integrate genetic and environmental influences to dysregulate neurodevelopmental processes. The objective of this review is to illustrate how epigenetic modifications that are known to alter gene expression without changing primary DNA sequence may play a role in the etiology of ASD.

METHOD

In this review, we summarize current knowledge about epigenetic modifications to genes and genomic regions possibly involved in the etiology of ASD.

RESULTS

Several genetic syndromes comorbid with ASD, which include Rett, Fragile X, Prader-Willi, Angelman, and CHARGE (Coloboma of the eye, Heart defects, Atresia of the nasal choanae, Retardation of growth and/or development, Genital and/or urinary abnormalities, and Ear abnormalities and deafness), all demonstrate dysregulation of epigenetic marks or epigenetic mechanisms. We report also on genes or genomic regions exhibiting abnormal epigenetic regulation in association with either syndromic (15q11-13 maternal duplication) or nonsyndromic forms of ASD. Finally, we discuss the state of current knowledge regarding the etiologic role of environmental factors linked to both the development of ASD and epigenetic dysregulation.

CONCLUSION

Data reviewed in this article highlight a variety of situations in which epigenetic dysregulation is associated with the development of ASD, thereby supporting a role for epigenetics in the multifactorial etiologies of ASD.

Intragenic rearrangements in NRXN1 in three families with autism spectrum disorder, developmental delay, and speech delay

NRXN1 is highly expressed in brain and has been shown recently to be associated with ASD, schizophrenia, cognitive and behavioral abnormalities, and alcohol and nicotine dependence. We present three families, in whom we identified intragenic rearrangements within NRXN1 using a clinical targeted oligonucleotide array CGH. An approximately 380 kb deletion was identified in a woman with Asperger syndrome, anxiety, and depression and in all four of her children affected with autism, anxiety, developmental delay, and speech delay but not in an unaffected child. An approximately 180 kb tandem duplication was found in a patient with autistic disorder and cognitive delays, and in his mother and younger brother who have speech delay. An approximately 330 kb tandem duplication was identified in a patient with autistic features. As predicted by conceptual translation, all three genomic rearrangements led to the premature truncation of NRXN1. Our data support previous observations that NRXN1 may be pathogenic in a wide variety of psychiatric diseases, including autism spectrum disorder, global developmental delay, anxiety, and depression.

Clinical genetic testing for patients with autism spectrum disorders

BACKGROUND

Multiple lines of evidence indicate a strong genetic contribution to autism spectrum disorders (ASDs). Current guidelines for clinical genetic testing recommend a G-banded karyotype to detect chromosomal abnormalities and fragile X DNA testing, but guidelines for chromosomal microarray analysis have not been established.

PATIENTS AND METHODS

A cohort of 933 patients received clinical genetic testing for a diagnosis of ASD between January 2006 and December 2008. Clinical genetic testing included G-banded karyotype, fragile X testing, and chromosomal microarray (CMA) to test for submicroscopic genomic deletions and duplications. Diagnostic yield of clinically significant genetic changes was compared.

RESULTS

Karyotype yielded abnormal results in 19 of 852 patients (2.23% [95% confidence interval (CI): 1.73%-2.73%]), fragile X testing was abnormal in 4 of 861 (0.46% [95% CI: 0.36%-0.56%]), and CMA identified deletions or duplications in 154 of 848 patients (18.2% [95% CI: 14.76%-21.64%]). CMA results for 59 of 848 patients (7.0% [95% CI: 5.5%-8.5%]) were considered abnormal, which includes variants associated with known genomic disorders or variants of possible significance. CMA results were normal in 10 of 852 patients (1.2%) with abnormal karyotype due to balanced rearrangements or unidentified marker chromosome. CMA with whole-genome coverage and CMA with targeted genomic regions detected clinically relevant copy-number changes in 7.3% (51 of 697) and 5.3% (8 of 151) of patients, respectively, both higher than karyotype. With the exception of recurrent deletion and duplication of chromosome 16p11.2 and 15q13.2q13.3, most copy-number changes were unique or identified in only a small subset of patients.

CONCLUSIONS

CMA had the highest detection rate among clinically available genetic tests for patients with ASD. Interpretation of microarray data is complicated by the presence of both novel and recurrent copy-number variants of unknown significance. Despite these limitations, CMA should be considered as part of the initial diagnostic evaluation of patients with ASD.

The clinical context of copy number variation in the human genome

During the past five years, copy number variation (CNV) has emerged as a highly prevalent form of genomic variation, bridging the interval between long-recognised microscopic chromosomal alterations and single-nucleotide changes. These genomic segmental differences among humans reflect the dynamic nature of genomes, and account for both normal variations among us and variations that predispose to conditions of medical consequence. Here, we place CNVs into their historical and medical contexts, focusing on how these variations can be recognised, documented, characterised and interpreted in clinical diagnostics. We also discuss how they can cause disease or influence adaptation to an environment. Various clinical exemplars are drawn out to illustrate salient characteristics and residual enigmas of CNVs, particularly the complexity of the data and information associated with CNVs relative to that of single-nucleotide variation. The potential is immense for CNVs to explain and predict disorders and traits that have long resisted understanding. However, creative solutions are needed to manage the sudden and overwhelming burden of expectation for laboratories and clinicians to assay and interpret these complex genomic variations as awareness permeates medical practice. Challenges remain for understanding the relationship between genomic changes and the phenotypes that might be predicted and prevented by such knowledge.

Autism

Autism spectrum disorders are characterised by severe deficits in socialisation, communication, and repetitive or unusual behaviours. Increases over time in the frequency of these disorders (to present rates of about 60 cases per 10,000 children) might be attributable to factors such as new administrative classifications, policy and practice changes, and increased awareness. Surveillance and screening strategies for early identification could enable early treatment and improved outcomes. Autism spectrum disorders are highly genetic and multifactorial, with many risk factors acting together. Genes that affect synaptic maturation are implicated, resulting in neurobiological theories focusing on connectivity and neural effects of gene expression. Several treatments might address core and comorbid symptoms. However, not all treatments have been adequately studied. Improved strategies for early identification with phenotypic characteristics and biological markers (eg, electrophysiological changes) might hopefully improve effectiveness of treatment. Further knowledge about early identification, neurobiology of autism, effective treatments, and the effect of this disorder on families is needed.

Syndromic autism: causes and pathogenetic pathways

BACKGROUND

Autism is a severe neurodevelopmental disorder known to have many different etiologies. In the last few years, significant progresses have been made in comprehending the causes of autism and their multiple impacts on the developing brain. This article aims to review the current understanding of the etiologies and the multiple pathogenetic pathways that are likely to lead to the autistic phenotype.

DATA SOURCES

The PubMed database was searched with the keywords "autism" and "chromosomal abnormalities", "metabolic diseases", "susceptibility loci".

RESULTS

Genetic syndromes, defined mutations, and metabolic diseases account for less than 20% of autistic patients. Alterations of the neocortical excitatory/inhibitory balance and perturbations of interneurons' development represent the most probable pathogenetic mechanisms underlying the autistic phenotype in fragile X syndrome and tuberous sclerosis complex. Chromosomal abnormalities and potential candidate genes are strongly implicated in the disruption of neural connections, brain growth and synaptic/dendritic morphology. Metabolic and mitochondrial defects may have toxic effects on the brain cells, causing neuronal loss and altered modulation of neurotransmission systems.

CONCLUSIONS

A wide variety of cytogenetic abnormalities have been recently described, particularly in the low functioning individuals with dysmorphic features. Routine metabolic screening studies should be performed in the presence of autistic regression or suggestive clinical findings. As etiologies of autism are progressively discovered, the number of individuals with idiopathic autism will progressively shrink. Studies of genetic and environmentally modulated epigenetic factors are beginning to provide some clues to clarify the complexities of autism pathogenesis. The role of the neuropediatrician will be to understand the neurological basis of autism, and to identify more homogenous subgroups with specific biologic markers.

Multiple rare variants in the etiology of autism spectrum disorders

Recent studies in autism spectrum disorders (ASDs) support an important role for multiple rare variants in these conditions. This is a clinically important finding, as, with the demonstration that a significant proportion of ASDs are the result of rare, etiological genetic variants, it becomes possible to make use of genetic testing to supplement behavioral analyses for an earlier diagnosis. As it appears that earlier interventions in ASDs will produce better outcomes, the development of genetic testing to augment behaviorally based evaluations in ASDs holds promise for improved treatment. Furthermore, these rare variants involve synaptic and neuronal genes that implicate specific paihvi/ays, cells, and subcellular compartments in ASDs, which in turn will suggest novel therapeutic approaches in ASDs, Of particular recent interest are the synaptic cell adhesion and associated molecules, including neurexin 1, neuroligin 3 and 4, and SHANK3, which implicate glutamatergic synapse abnormalities in ASDs, In the current review we will overview the evidence for a genetic etiology for ASDs, and summarize recent genetic findings in these disorders.

Recent advances in the pathogenesis of syndromic autisms

Background. Current advances in genetic technology continue to expand the list of medical conditions associated with autism. Clinicians have to identify specific autistic-related syndromes, and to provide tailored counseling. The aim of this study is to elucidate recent advances in autism research that offer important clues into pathogenetic mechanisms of syndromic autism and relevant implications for clinical practice. Data Sources. The PubMed database was searched with the keywords “autism” and “chromosomal abnormalities,” “metabolic diseases,” “susceptibility loci.” Results. Defined mutations, genetic syndromes, and metabolic diseases account for up to 20% of autistic patients. Metabolic and mitochondrial defects may have toxic effects on the brain cells, causing neuronal loss and altered modulation of neurotransmission systems. Alterations of the neocortical excitatory/inhibitory balance and perturbations of interneurons' development represent the most probable pathogenetic mechanisms underlying the autistic phenotype in Fragile X-Syndrome and Tuberous Sclerosis Complex. Chromosomal abnormalities and potential candidate genes are strongly implicated in the disruption of neural connections, brain growth, and synaptic/dendritic morphology. Conclusion. Metabolic testing may be appropriate if specific symptoms are present. High-resolution chromosome analysis may be recommended if a specific diagnosis is suspected because of obvious dysmorphisms. Identifying cryptic chromosomal abnormalities by whole genome microarray analysis can increase the understanding of the neurobiological pathways to autism.

Parents' perceptions of autism spectrum disorder etiology and recurrence risk and effects of their perceptions on family planning: Recommendations for genetic counselors

Knowledge about the etiology of Autism Spectrum Disorders (ASDs) is increasing, but causes remain elusive for most cases. Genetic counselors are positioned to help families that have children with ASDs despite uncertainty regarding etiology. To determine how genetic counselors might best provide services, an anonymous survey was conducted with 255 parents whose children were diagnosed on the autism spectrum. Questions concerned: 1) their perceptions of ASD cause(s) and 2) recurrence risk, 3) whether perceived risk affected family planning decisions, 4) whether parents had received genetic services, and 5) how genetic counselors might assist families. The most prevalent perceived cause was genetic influences (72.6%). Most parents' recurrence risk perceptions were inaccurately high and significantly affected family planning. Only 10% had seen a genetic professional related to an ASD. Parents provided several suggestions for genetic counselor best practices. Findings indicate the importance of genetic counselor awareness of parent perceptions in order to best help families who have children with ASDs.

Parents' reports predict abnormal investigations in global developmental delay

AIMS

To identify symptoms reported by parents that predict abnormal laboratory investigations in preschoolers with global developmental delay (GDD).

METHODS

A cross-sectional descriptive study of 81 boys and 38 girls, with a mean age of 43.5 months (SD = 13.4), with global developmental delay. All parents/guardians completed the following: (1) a semistructured interview about their child and family; (2) the Child Development Inventory (CDI); (3) the Possible Problems Checklist (PPC); and (4) the Child Behavior Checklist 1(1/2)-5 (CBCL).

RESULTS

There were 61 abnormal results: MRI 37 (31%); high-resolution chromosomes 8 (7%); fragile X molecular testing 4 (3%); and microarray comparative genomic hybridization 12 (10%). A total of 47 children had abnormal tests (40%): none, 72 (60%); one, 36 (30%); two, 8 (7%); three, (3%). Younger children with more developmental delays are more likely to have abnormal tests. They are clumsy, more passive, and less disobedience. They had lower total, externalizing, and internalizing problems scores. The odds of finding an abnormal investigation are increasingly greater as parent's report of language comprehension and social development ratios increase, and decrease in likelihood for every increase in the expressive language and fine motor ratios.

INTERPRETATION

Parent's reports predict abnormal tests and indicate quantifiable differences requiring investigation.

Hypo-phosphorylation of salivary peptidome as a clue to the molecular pathogenesis of autism spectrum disorders

RP-HPLC-ESI-MS profile of naturally occurring salivary peptides of subjects with autistic spectrum disorder [ASD; N = 27:12 with diagnosis of autism, 1 with diagnosis of Asperger, 14 with diagnosis of pervasive developmental disorders not otherwise specified (PDD-NOS)] was compared to that of age-matched controls with the goal of identifying differences that could turn out to become hallmarks of at least a subgroup of ASD individuals. Phosphorylation level of four specific salivary phospho-peptides, namely statherin, histatin 1 (both, p < 0.0001) and acidic proline-rich proteins (both entire and truncated isoforms) (p < 0.005) was found significantly lower in autistic patients, with hypo-phosphorylation of at least one peptide observed in 18 ASD subjects (66%). Developmental scale assessment (Griffith or WISC-R) carried out on 14 ASD subjects highlighted a normal to borderline cognitive development in 10 of them, all included in the hypo-phosphorylated group. Phosphorylation of salivary peptides involves a Golgi casein kinase common to many organs and tissues, CNS included, whose expression seems to be synchronized during fetal development. Hypo-phosphorylation of salivary peptides suggests potential asynchronies in the phosphorylation of other secretory proteins, which could be relevant in CNS development either during embryonic development or in early infancy. These results suggest that analysis of salivary phospho-peptides might help to discriminate a considerable subgroup of ASD patients.

Microarray-Based Genomic DNA Profiling Technologies in Clinical Molecular Diagnostics

Background: Microarray-based genomic DNA profiling (MGDP) technologies are rapidly moving from translational research to clinical diagnostics and have revolutionized medical practices. Such technologies have shown great advantages in detecting genomic imbalances associated with genomic disorders and single-gene diseases.

Content: We discuss the development and applications of the major array platforms that are being used in both academic and commercial laboratories. Although no standardized platform is expected to emerge soon, comprehensive oligonucleotide microarray platforms—both comparative genomic hybridization arrays and genotyping hybrid arrays—are rapidly becoming the methods of choice for their demonstrated analytical validity in detecting genomic imbalances, for their flexibility in incorporating customized designs and updates, and for the advantage of being easily manufactured. Copy number variants (CNVs), the form of genomic deletions/duplications detected through MGDP, are a common etiology for a variety of clinical phenotypes. The widespread distribution of CNVs poses great challenges in interpretation. A broad survey of CNVs in the healthy population, combined with the data accumulated from the patient population in clinical laboratories, will provide a better understanding of the nature of CNVs and enhance the power of identifying genetic risk factors for medical conditions.

Summary: MGDP technologies for molecular diagnostics are still at an early stage but are rapidly evolving. We are in the process of extensive clinical validation and utility evaluation of different array designs and technical platforms. CNVs of currently unknown importance will be a rich source of novel discoveries.

Contemplating effects of genomic structural variation

Two developments have sparked new directions in the genetics-to-genomics transition for research and medical applications: the advance of whole-genome assays by array or DNA sequencing technologies, and the discovery among human genomes of extensive submicroscopic genomic structural variation, including copy number variation. For health care to benefit from interpretation of genomic data, we need to know how these variants contribute to the phenotype of the individual. Research is revealing the spectrum, both in size and complexity, of structural genotypic variation, and its association with a broad range of human phenotypes. Genomic disorders associated with relatively large, recurrent contiguous variants have been recognized for some time, as have certain Mendelian traits associated with functional disruption of single genes by structural variation. More recent examples from phenotype- and genotype-driven studies demonstrate a greater level of complexity, with evidence of incremental dosage effects, gene interaction networks, buffering and modifiers, and position effects. Mechanisms underlying such variation are emerging to provide a handle on the bulk of human variation, which is associated with complex traits and adaptive potential. Interpreting genotypes for personalized health care and communicating knowledge to the individual will be significant challenges for genomics professionals.

Potential for early-life immune insult including developmental immunotoxicity in autism and autism spectrum disorders: focus on critical windows of immune vulnerability

Early-life immune insults (ELII) including xenobiotic-induced developmental immunotoxicity (DIT) are important factors in childhood and adult chronic diseases. However, prenatal and perinatal environmentally induced immune alterations have yet to be considered in depth in the context of autism and autism spectrum disorders (ASDs). Numerous factors produce early-life-induced immune dysfunction in offspring, including exposure to xenobiotics, maternal infections, and other prenatal-neonatal stressors. Early life sensitivity to ELII, including DIT, results from the heightened vulnerability of the developing immune system to disruption and the serious nature of the adverse outcomes arising after disruption of one-time immune maturational events. The resulting health risks extend beyond infectious diseases, cancer, allergy, and autoimmunity to include pathologies of the neurological, reproductive, and endocrine systems. Because these changes may include misregulation of resident inflammatory myelomonocytic cells in tissues such as the brain, they are a potential concern in cases of prenatal-neonatal brain pathologies and neurobehavioral deficits. Autism and ASDs are chronic developmental neurobehavioral disorders that are on the rise in the United States with prenatal and perinatal environmental factors suspected as contributors to this increase. Evidence for an association between environmentally associated childhood immune dysfunction and ASDs suggests that ELII and DIT may contribute to these conditions. However, it is not known if this linkage is directly associated with the brain pathologies or represents a separate (or secondary) outcome. This review considers the known features of ELII and DIT and how they may provide important clues to prenatal brain inflammation and the risk of autism and ASDs.