The genetics of autism

Total Reflection X-ray Fluorescence Analysis of Plasma Elements in Autistic Children from India

Trace elements are essential for the human body's various physiological processes but if they are present in higher concentration, these elements turn to be toxic and cause adverse effect on physiological processes. Similarly, deficiency of these essential elements also affects physiological processes and leads to abnormal metabolic activities. There is a lot of interest in recent years to know the mystery behind the involvement of trace elements in the metabolic activities of autistic children suspecting that it may be a risk factor in the aetiology of autism. The present study aims to analyse the plasma trace elements in autistic children using the total reflection X-ray fluorescence (TXRF) technique. Plasma samples from 70 autistic children (mean age: 11.5 ± 3.1) were analysed with 70 age- and sex-matched healthy children as controls (mean age: 12 ± 2.5). TXRF analysis revealed the higher concentration of copper (1227.8 ± 17.8), chromium (7.1 ± 2.5), bromine (2695.1 ± 24) and arsenic (126.3 ± 10) and lower concentration of potassium (440.1 ± 25), iron (1039.6 ± 28), zinc (635.7 ± 21), selenium (52.3 ± 8.5), rubidium (1528.9 ± 28) and molybdenum (162,800.8 ± 14) elements in the plasma of autistic children in comparison to healthy controls. Findings of the first study from India suggest these altered concentrations in elements in autistic children over normal healthy children affect the physiological processes and metabolism. Further studies are needed to clarify the association between the altered element concentration and physiology of autism in the North Karnataka population in India.

Biolinguistics: A Scientometric Analysis of Research on (Children's) Molecular Genetics of Speech and Language (Disorders)

There are numerous children and adolescents throughout the world who are either diagnosed with speech and language disorders or manifest any of them as a result of another disorder. Meanwhile, since the emergence of language as an innate capability, the question of whether it constitutes a behaviour or an innate ability has been debated for decades. There have been several theories developed that support and demonstrate the biological foundations of human language. Molecular evidence of the biological basis of language came from the FOXP2 gene, also known as the language gene. Taking a closer look at both human language and biology, biolinguistics is at the core of these inquiries-attempting to understand the aetiologies of the genetics of speech and language disorders in children and adolescents. This paper presents empirical evidence based on both scientometrics and bibliometrics. We collected data between 1935 and 2022 from Scopus, WOS, and Lens. A total of 1570 documents were analysed from Scopus, 1440 from the WOS, and 5275 from Lens. Bibliometric analysis was performed using Excel based on generated reports from these three databases. CiteSpace 5.8.R3 and VOSviewer 1.6.18 were used to conduct the scientometric analysis. Eight bibliometric and eight scientometric indicators were used to measure the development of the field of biolinguistics, including but not limited to the production size of knowledge, the most examined topics, and the most frequent concepts and variables. A major finding of our study is identifying the most examined topics in the genetics of speech and language disorders. These included: gestural communication, structural design, cultural evolution, neural network, language tools, human language faculty, evolutionary biology, molecular biology, and theoretical perspective on language evolution.

Genetic analysis of the postsynaptic transmembrane X-linked neuroligin 3 gene in autism

Autism is a complex neurodevelopmental disorder, the prevalence of which has increased drastically in India in recent years. Neuroligin is a type I transmembrane protein that plays a crucial role in synaptogenesis. Alterations in synaptic genes are most commonly implicated in autism and other cognitive disorders. The present study investigated the neuroligin 3 gene in the Indian autistic population by sequencing and in silico pathogenicity prediction of molecular changes. In total, 108 clinically described individuals with autism were included from the North Karnataka region of India, along with 150 age-, sex-, and ethnicity-matched healthy controls. Genomic DNA was extracted from peripheral blood, and exonic regions were sequenced. The functional and structural effects of variants of the neuroligin 3 protein were predicted. One coding sequence variant (a missense variant) and four non-coding variants (two 5'-untranslated region [UTR] variants and two 3'-UTR variants) were recorded. The novel missense variant was found in 25% of the autistic population. The C/C genotype of c.551T>C was significantly more common in autistic children than in controls (p = 0.001), and a significantly increased risk of autism (24.7-fold) was associated with this genotype (p = 0.001). The missense variant showed pathogenic effects and high evolutionary conservation over the functions of the neuroligin 3 protein. In the present study, we reported a novel missense variant, V184A, which causes abnormal neuroligin 3 and was found with high frequency in the Indian autistic population. Therefore, neuroligin is a candidate gene for future molecular investigations and functional analysis in the Indian autistic population.

Genetic Analysis of Neuroligin 4Y Gene in Autism Population of India

Background  Autism is one of the most complex, heterogeneous neurological disorders. It is characterized mainly by abnormal communication, impaired social interaction, and restricted behaviors. Prevalence of autism is not clear in Indian population.

Aim  The present study hypothesized that Y chromosome plays role in sex bias of autism in Indian autistic population. To investigate our hypothesis, we underwent genetic analysis of neuroligin 4Y [ NLGN4Y ] gene by sequencing 85 male autistic children after screening large population of 1,870 mentally ill children from North Karnataka region of India.

Result  Detailed sequencing of the single targeted gene revealed nine variants including, one novel missense mutation and eight synonymous variants; this accounts for 88.9% of synonymous variants. A single novel missense mutation is predicted to be nonpathogenic on the functions of neuroligin4Y protein but it slightly affects the local configuration by altering the original structure of a protein by changing charge and size of amino acid.

Conclusion  Probably NLGN4Y gene may not be the risk factor for autism in male children in Indian autistic population. Functional analysis was an important limitation of our study. Therefore, detailed functional analysis is necessary to determine the exact role of novel missense mutation of neuroligin 4Y [ NLGN4Y ] gene especially in the male predominance of autism in Indian autistic population.

Pathogenic Yield of Genetic Testing in Autism Spectrum Disorder

BACKGROUND AND OBJECTIVES

Genetic testing is recommended for individuals with autism spectrum disorder (ASD). Pathogenic yield varies by clinician and/or patient characteristics. Our objectives were to determine the pathogenic yield of genetic testing, the variability in rate of pathogenic results based on subject characteristics, and the percentage of pathogenic findings resulting in further medical recommendations in toddlers with a Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition diagnosis of ASD.

METHODS

We conducted a retrospective chart review of 500 toddlers, 18 to 36 months, diagnosed with Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition ASD (mean age: 25.8 months, 79% male). Subject demographics, medical and neuropsychological characteristics, and genetic test results were abstracted. Genetic results were divided into negative or normal, variants of unknown significance, and pathogenic. Subject characteristics were compared across results. Manual chart review determined if further recommendations were made after pathogenic results.

RESULTS

Over half of subjects (59.8%, n = 299) completed genetic testing, and of those, 36 (12.0%) had pathogenic findings. There were no significant differences in Bayley Scales of Infant Development cognitive (P = .112), language (P = .898), or motor scores (P = .488) among children with negative or normal findings versus a variant of unknown significance versus pathogenic findings. Medical recommendations in response to the genetic finding were made for 72.2% of those with pathogenic results.

CONCLUSIONS

Our findings reinforce the importance of genetic testing for toddlers diagnosed with ASD given the 12% yield and lack of phenotypic differences between subjects with and without pathogenic findings. The majority of pathogenic results lead to further medical recommendations.

Oxidative stress, metabolic and mitochondrial abnormalities associated with autism spectrum disorder

Autism spectrum disorder is a neurodevelopmental disorder characterized by impaired development and by abnormal function in regards to social interaction, communication and restricted, repetitive behavior. It affects approximately 1% of the worldwide population. Like other psychiatric disorders the diagnosis is based on observation of, and interview with the patient and next of kin, and diagnostic tests. Many genes have been associated with autism, but only few highly penetrant. Some researchers have instead focused on oxidative stress, metabolic abnormalities and mitochondrial dysfunction as an explanation of the disorder. Currently no cure exists for the disorder, making these abnormalities interesting as they are possibly correctable with supplements or treatment. These various processes cannot be seen independently as they are influencing and interacting with each other. Furthermore many of the metabolic changes seen in autism have also been shown in other psychiatric disorders such as attention deficit hyperactivity disorder, schizophrenia and bipolar disorder along with often comorbid disorders like epilepsy and intellectual disability. As such some of these abnormalities are not specific, however, could indicate a similar mechanism for the development of these disorders, with symptomatology and severity varying according to the location and the amount of damage done to proteins, cells and DNA. Clinical studies trying to treat these abnormalities, have widely been successful in correcting the metabolic abnormalities seen, but only some studies have also shown bettering of autistic symptoms. Hopefully with increased knowledge of the pathophysiology of the disorder, future preventive measures or treatment can be developed.

Brain Organoids as Tools for Modeling Human Neurodevelopmental Disorders

Brain organoids recapitulate in vitro the specific stages of in vivo human brain development, thus offering an innovative tool by which to model human neurodevelopmental disease. We review here how brain organoids have been used to study neurodevelopmental disease and consider their potential for both technological advancement and therapeutic development.

Sleep Disturbances in Neurodevelopmental Disorders

Sleep disturbances are extremely prevalent in children with neurodevelopmental disorders compared to typically developing children. The diagnostic criteria for many neurodevelopmental disorders include sleep disturbances. Sleep disturbance in this population is often multifactorial and caused by the interplay of genetic, neurobiological and environmental overlap. These disturbances often present either as insomnia or hypersomnia. Different sleep disorders present with these complaints and based on the clinical history and findings from diagnostic tests, an appropriate diagnosis can be made. This review aims to provide an overview of causes, diagnosis, and treatment of sleep disturbances in neurodevelopmental disorders that present primarily with symptoms of hypersomnia and/or insomnia.

Macrocephaly as a clinical indicator of genetic subtypes in autism

An association between autism and macrocephaly has been previously described. A subset of cases with extreme macrocephaly (>3 standard deviation [SD], 99.7th percentile) have been correlated to mutations in the gene phosphatase and tensin homolog (PTEN). However, the phenotypic and genetic characterization of the remaining cases remains unclear. We report the phenotypic classification and genetic testing evaluation of a cohort of 33 patients with autism and macrocephaly. Within our cohort, we confirm the association of PTEN mutations and extreme macrocephaly (>3 SD, 99.7th percentile) and identify mutations in 22% of cases, including three novel PTEN mutations. In addition, we define three phenotypic subgroups: (a) those cases associated with somatic overgrowth, (b) those with disproportionate macrocephaly, and (c) those with relative macrocephaly. We have devised a novel way to segregate patients into these subgroups that will aide in the stratification of autism macrocephaly cases. Within these subgroups, we further expand the genetic etiologies for autism cases with macrocephaly by describing two novel suspected pathogenic copy number variants located at 6q23.2 and 10q24.32. These findings demonstrate the phenotypic heterogeneity of autism cases associated with macrocephaly and their genetic etiologies. The clinical yield from PTEN mutation analysis is 22% and 9% from chromosomal microarray (CMA) testing within this cohort. The identification of three distinct phenotypic subgroups within macrocephaly autism patients may allow for the identification of their respective distinct genetic etiologies that to date have remained elusive.

Diagnosing Autism in Individuals with Known Genetic Syndromes: Clinical Considerations and Implications for Intervention

Assessing symptoms of autism in persons with known genetic syndromes associated with intellectual and/or developmental disability is a complex clinical endeavor. We suggest that a developmental approach to evaluation is essential to reliably teasing apart global impairments from autism-specific symptomology. In this chapter, we discuss our assumptions about autism spectrum disorders, the process of conducting a family-focused, comprehensive evaluation with behaviorally complex children and some implications for intervention in persons with co-occurring autism and known genetic syndromes.

Immune therapy in autism: historical experience and future directions with immunomodulatory therapy

Autism affects 1 in 110 new births, and it has no single etiology with uniform agreement. This has a significant impact on the quality of life for individuals who have been diagnosed with autism. Although autism has a spectrum quality with a shared diagnosis, it presents a uniquely different clinical appearance in each individual. Recent research of suspected immunological factors have provided more support for a probable immunological process or for processes that may play a role in the acquisition of an autistic condition. These factors include prenatal, genetic, and postnatal findings, as well as the discovery of a dysfunctional chronic pro-inflammatory state in brain tissue and cerebrospinal fluid in subsets of autistic patients. These findings offer new theories that may lead to the development of disease modification or preventative therapeutic options in the near future. This article reviews prenatal, genetic, and observed immune aspects of the autism condition that may be risk factors in the presentation of the autistic clinical phenotype. Historical immune interventions in autism are reviewed and potential new therapies and interventions are discussed.

Disparities in diagnosis and access to health services for children with autism: data from the National Survey of Children's Health

OBJECTIVE

Earlier assessment of autism improves outcomes. In addition, children with autism have significant need for medical care. Therefore, identification of factors associated with delays in the early diagnosis of autism and with decreased access to care has the potential to lead to interventions that will improve health and well-being. The aim of this study was to determine whether differences occur in the age-specific prevalence of autism or in access to health care in children of traditionally underserved populations.

METHOD

Data from the National Survey of Children's Health of 2003/2004 were used. Diagnosis of autism and its severity were based on parental report.

RESULTS

The prevalence of autism was lower for Latinos (26/10,000) than for non-Latinos (51/10,000). Whites and blacks had comparable rates. The lowest preschool rate of autism (16/10,000) occurred in poor children. Latinos and poor families rated their children's autism as more severe. Being black, Latino, or poor was associated with decreased access to services, while having Medicaid or State Children's Health Insurance Program was linked with better access to some services.

CONCLUSIONS

Disparities in the prevalence and parent-reported severity of autism and in access to health care were found for children with autism. Programs for children in general (e.g., universal screening for autism) and programs that target traditionally underserved groups of children, their families, and their health care providers should be tested and implemented to optimize case finding of children with autism and to eliminate disparities in access to care and to early intervention.

Copy number variation in the autism genome

BACKGROUND

Autism spectrum disorders (ASDs) are among the most heritable of all neurodevelopmental disorders. Despite intense research there has been limited success in deciphering the etiology of ASDs.

OBJECTIVE

It has been shown that chromosomal rearrangements play an important role in ASDs. The recent development of techniques to screen the genome for genetic variation at ever-higher resolution has led to some crucial discoveries over the last year. This progress is described and discussed.

METHODS

This review provides an overview of genetic variation studies in ASD, with a focus on structural genetic variation.

RESULTS/CONCLUSION

Screening for copy number variation is an important approach in ASD research. With the introduction of next-generation sequencing, the pace of ASD genetics will increase in the near future.

Clinical genetics evaluation in identifying the etiology of autism spectrum disorders

The autism spectrum disorders are a collection of conditions, which have, in common, impaired socialization and communication in association with stereotypic behaviors. The reported incidence of autism spectrum disorders has increased markedly over the past decade. In addition, a large amount of attention has been paid to these conditions among lay and professional groups. These influences have resulted in a marked increase in the number of referrals to clinical geneticists for evaluation of persons with autism spectrum disorders. The primary role of the geneticist in this process is to define etiology, if possible, and to provide counseling and contribute to case management based on the results of such investigations. In deciding upon the appropriate evaluation scheme for a particular patient, the geneticist must consider a host of different factors. Such considerations would include (1) Assuring an accurate diagnosis of autism before proceeding with any investigation. (2) Discussing testing options, diagnostic yields, and patient investment before proceeding with an evaluation. (3) Communication and coordination with the patient's medical home. (4) Assessing the continuously expanding and evolving list of available laboratory testing modalities in light of evidence-based medicine. (5) Recognizing expanded phenotypes of well-described syndromic and metabolic conditions that encompass autism spectrum disorders. (6) Defining an individualized evaluation scheme based on the unique history and clinical features of a given patient. The guidelines in this article have been developed to assist the clinician in the consideration of these factors.

Genetic evaluation of autism

The autism spectrum disorders represent a collective of neurogenetic conditions that have in common altered socialization and communication. Much attention has been given lately to the marked increased in the reported incidence of these conditions. Significant debate also exists as to the basis of the reported increase. Regardless, clinical geneticists and pediatric neurologists alike are seeing a tremendous increase in the number of referrals for autism and related conditions. Continuing advances in genetic testing provide a moving target for the clinician in determining an appropriate diagnostic plan. In this article, we review the most recent advances in genetic testing technology and their potential application to the etiologic evaluation of patients with autism spectrum disorders.

Do hyperactivity, impulsivity and inattention have an impact on the ability of facial affect recognition in children with autism and ADHD?

Psychopathological, genetic and neuropsychological findings indicate an association between autism and attention deficit/hyperactivity disorder (ADHD). The goal of this study was to assess possible differences in facial affect recognition in children with autism (with and without comorbid ADHD), with ADHD and healthy controls. Children aged 6-18 years old with DSM-IV-diagnosis ADHD (n=30) or autism (n=40) were included consecutively in the study. Facial affect recognition was assessed with a computer-based program used for teaching emotion processing called the Frankfurt Test and Training of Social Affect (FEFA) using faces and eye-pairs as target material. Additionally three attention-tasks (Sustained attention, Inhibition, Set-Shifting) were administered. Approximately 52% of the autistic children met the criteria for the comorbid diagnosis of ADHD. A MANOVA with post-hoc Scheffé tests revealed a significant difference in the recognition of faces and eye pairs between the group ADHD and controls (P=0.009). Children with autism and ADHD also differed significantly from healthy participants in the recognition of eye-pairs (P=0.009). Neither correlations with PDD nor with ADHD symptom scores were able to explain these results. Sustained attention and inhibition deficits had a significant influence on emotion recognition in children with ADHD. Our findings imply that the ability of facial affect recognition is reduced in children suffering from ADHD symptoms, both in autistic and pure ADHD children. ADHD symptoms need to be taken into account in future studies assessing emotion recognition in autistic children and adolescents.

Variation in season of birth in singleton and multiple births concordant for autism spectrum disorders

Patterns of seasonal variation in births in some neuropsychiatric conditions have been found in previous research; however, no study to date has examined these disorders for seasonal variation in singletons and multiple births separately. This study aimed to determine whether the birth date distribution for individuals with autism spectrum disorders (ASD), including singletons and multiple births, differed from the general population. Two ASD case groups were studied: 907 singletons and 161 multiple births concordant for ASD. Two control groups were obtained from registered births of singletons and multiples. Results of the non-parametric time-series analyses, where day of birth was used, suggested there were three peaks in ASD singletons and ASD concordant multiple births. Roughly, the peaks were in April, June and October for singletons and about 2-4 weeks earlier in multiples. Results from multivariable Poisson regression, where month of birth was used, indicated that ASD concordant multiple births in males tended to be higher than expected in March, May and September (with borderline statistical significance), but were 87% less in December (P < 0.05), as compared with January. Overall, the patterns of relative risk estimates from Poisson regression are similar to findings from the non-parametric time-series approach, but are not exactly congruent. It is important to note that indications of seasonality may be sensitive to the selection of time cut-points and therefore an arbitrary binning of time can either mask existing trends or falsely indicate the presence of a trend. The presence of seasonal trends in ASD singletons and concordant multiple births suggests a role for non-heritable factors operating during the pre- or perinatal period, even among cases with a genetic susceptibility.

Genetic testing in autism: how much is enough?

PURPOSE

To evaluate the yield of genetic testing in children with autism spectrum disorders.

METHODS

We performed a retrospective chart review of 71 unrelated patients with a diagnosis of an isolated autism spectrum disorder seen in a genetics clinic over a period of 14 months. For most, referrals occurred after evaluation by a developmental pediatrician and/or psychologist to establish the diagnosis. Tiered laboratory testing for the majority of the patients followed a guideline that was developed in collaboration with clinicians at The Autism Center at Children's Hospital, Columbus, OH.

RESULTS

The patients included 57 males and 14 females; 57 met DSM-IV criteria for autism, with the rest being Asperger or pervasive developmental disorder not otherwise specified. Macrocephaly [head circumference (HC) >or=95%] was present in 19 (27%). Two children had visible chromosome abnormalities (47,XYY; 48,XY + 2mar/49,XY + 3mar). Two patients with autism and macrocephaly had heterozygous mutations in the PTEN tumor suppressor gene. Three females had Rett syndrome, each confirmed by DNA sequencing of the MECP2 gene. Extensive metabolic testing produced no positive results, nor did fragile X DNA testing.

CONCLUSION

The overall diagnostic yield was 10% (7/71). PTEN gene sequencing should be considered in any child with macrocephaly and autism or developmental delay. Metabolic screening may not be warranted in autism spectrum disorders without more specific indications or additional findings.

Autism from developmental and neuropsychological perspectives

In this review of the research literature on autism, we argue that the application of developmental and neuropsychological perspectives has contributed importantly to the understanding of the core deficits in autism and their underlying neural bases. The three classes of theories postulated to explain the developmental and neuropsychological deficits in autism are considered in terms of the specificity, uniqueness, and universality of these impairments in autism. Because we believe that a primary reason for our lack of understanding of the developmental trajectory in autism stems from our inability to diagnose the syndrome in the first three years of life, research approaches to early identification are discussed, as are longitudinal studies aimed at identifying later-life outcomes and their predictors. In contrast to the progress made in defining the core deficits and arriving at criteria for diagnosis, less progress has been made in identifying the causes of autism and in creating and testing interventions aimed at ameliorating the impairments of autism, possibly because these activities have been less tied to the developmental and neuropsychological models that have enlightened the investigation of core deficits.

Increasing knowledge of PTEN germline mutations: Two additional patients with autism and macrocephaly

Recently, Butler et al. [2005; J Med Genet 42:318-321] reported the presence of heterozygous germline mutations in the PTEN tumor suppressor gene in three children with autism and macrocephaly. Here, we report the presence of PTEN mutations in two additional unrelated children with macrocephaly and autism. Our findings extend those of Butler et al. and suggest that PTEN gene sequencing should be included in the genetic evaluation of this subset of autistic individuals.

A case of pervasive developmental disorder with chromosomal translocation 1-4

We describe a 5-year-old girl with pervasive developmental disorder associated to chromosome 1-4 translocation, an association that has not been described in specialized literature until this moment.

Autism spectrum disorders: developmental disconnection syndromes

Autism is a common and heterogeneous childhood neurodevelopmental disorder. Analogous to broad syndromes such as mental retardation, autism has many etiologies and should be considered not as a single disorder but, rather, as 'the autisms'. However, recent genetic findings, coupled with emerging anatomical and functional imaging studies, suggest a potential unifying model in which higher-order association areas of the brain that normally connect to the frontal lobe are partially disconnected during development. This concept of developmental disconnection can accommodate the specific neurobehavioral features that are observed in autism, their emergence during development, and the heterogeneity of autism etiology, behaviors and cognition.

What do we know about the serotonergic genetic heterogeneity in attention-deficit/hyperactivity and autistic disorders?

BACKGROUND

Shared candidate gene regions point to a link between autistic disorders and attention-deficit/hyperactivity disorder (ADHD). Although they represent nosologically different diagnoses, the disorders do show some shared symptoms, above all inattention. For both disorders, the association with the serotonergic system is a focus of current research.

SAMPLING AND METHODS

The current work provides an overview of serotonergic mechanisms in ADHD and autistic disorders as well as the resulting pharmacogenetic approaches.

RESULTS

No uniform picture emerges either for ADHD or for autistic disorders. In pharmacogenetic terms, there are some isolated studies on associations between serotonergic mechanisms and pharmacotherapy. For the area of autism, such studies are still lacking.

CONCLUSIONS

The presented serotonergic mechanisms show relationships of this polymorphism to ADHD and autistic disorders, but they do not result in a uniform picture. The overlaps can best be explained by a dimensional classification approach. As yet, only a small number of studies on attentional disorders in autism and ADHD using shared samples have been carried out. With regard to diagnostics and therapy, analyses on the etiology of the attentional disorder of ADHD and autism are required.

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.

Diagnostic yield in the clinical genetic evaluation of autism spectrum disorders

PURPOSE

Clinical geneticists are often asked to evaluate patients with autism spectrum disorders (ASDs) in reference to questions about cause and recurrence risk. Recent advances in diagnostic testing technology have greatly increased the options available to them. It is not currently clear what the overall diagnostic yield of a battery of tests, either collectively or individually, might be. The purpose of this study was to evaluate the diagnostic yield of a stepwise approach we have implemented in our clinics.

METHODS

We used a three-tiered neurogenetic evaluation scheme designed to determine the cause of ASDs in patients referred for clinical genetic consultation. We reviewed the results of our diagnostic evaluations on all patients referred with a confirmed diagnosis of autism over a 3-year period.

RESULTS

By using this approach, we found an overall diagnostic yield for ASDs of more than 40%. This represents a significant increase in the diagnostic yield reported just a few years ago.

CONCLUSIONS

Given the implications of these diagnoses on recurrence risk and associated medical conditions, a targeted neurogenetic evaluation of all persons with ASDs seems warranted. We discuss the issues in the future implementation of a fourth tier to the evaluation with the potential for an even higher diagnostic yield.

Shared Susceptibility Region On Chromosome 15 Between Autism And Catatonia

We have compiled significant linkage results from 20 genome scans for the autism syndrome disorder (ASD) and 2 for catatonia in schizophrenia (SZ). Localization of the markers has been updated across the studies using the same cytological (Genetic Location Database), physical (National Center for Biological Information), and genetic (Marshfield) maps. Eight autosomal chromosomes (1, 2, 3, 7, 9, 13, 15, and 17) showed significant linkages with ASD, and one with catatonia (15). Chromosome 15 was further characterized for SZ genome scans (N = 4) since catatonia was observed in SZ patients, for candidate genes for ASD and catatonia, and for the numerous chromosomal rearrangement and abnormalities associated to ASD. From these results, we observed that four potential susceptibility regions for ASD could be observed on chromosome 15 at 15q11-q13, 15q14-q21, 15q22-q23, and 15q26, respectively. All the four regions were shared between ASD and SZ, with 15q15-q21 being also shared with catatonia. Strong candidate genes, such as gamma-aminobutyric acid receptor B3, A5, and G3, have shown associations with ASD at 15q11-q13 susceptibility region where the majority of the chromosomal rearrangements are also found. On the other hand, negative association results were observed at 15q14-q21 susceptibility region for catatonia with the genes encoding the zinc transporter SLC30A4, the cholinergic receptor nicotinic alpha polypeptide 7, and the delta-like 4 Drosophila. Further, fine mapping and candidate gene analyses are needed to highlight potential common genes between ASD and catatonia for this chromosome.

Sleep disorders, immunizations, sports injuries, autism

PURPOSE OF REVIEW

The purpose of this article is to summarize and synthesize the recent literature in four very important areas for pediatric office practice: sleep disorders, new immunizations, sports injuries, and autism. Important articles in each area are highlighted.

RECENT FINDINGS

The management of pediatric and adolescent sleep disorders is in the forefront of the pediatric literature. The most recent literature cautions practitioners on prescribing pharmacologic treatment for sleep problems in children and adolescents. Several new immunizations targeted for adolescents are on the horizon. The newest recommendations for their delivery are outlined here. Recent sports injury literature emphasizes the need of the practitioner to address sports injury prevention and to provide anticipatory guidance at pediatric office visits. Finally, the past year's literature demonstrates that there is significant interest in autism spectrum disorders, but the clinicians' challenge for making the correct diagnosis of these disorders remains.

SUMMARY

The literature presented and summarized here will give the practicing pediatrician practical working knowledge of four important office-based pediatric topics: sleep disorders, new immunizations, sports injuries, and autism.

Developmental Neurobiology and Clinical Disorders: Lost in Translation?

Advances in defining mechanisms of cortical development have been paralleled in recent years by an intense interest in translating these findings into greater insight of both childhood- and adult-onset cognitive and mental health disorders of developmental etiology. Successful integration of basic and clinical findings have been applied to monogenic disorders. The greater challenge lies in studying cortical development in the context of gene x environment interactions, which underlie the pathogenesis of the most common neurodevelopmental disorders. This can occur through an improved delineation of pathophysiological characteristics unique to specific complex disorders and the application of this information to the refinement of the most relevant model systems.