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PubMed2006

Magnesium profile in autism.

The aim of the present study was to determine and compare plasma and erythrocyte concentrations of magnesium in 12 autistic children (10 boys, 2 girls), 17 children with other autistic spectrum disorders (14 boys, 3 girls), 5 girls with classic Rett syndrome, and 14 normal children (7 boys, 7 girls) of the same age. No differences in intracellular Mg were found between controls and pathological subjects; however, autistic children and children with other autistic spectrum disorders had significantly lower plasma concentrations of Mg than normal subjects (p=0.013 and p=0.02, respectively). Although our study population was small, we conclude that children with autistic spectrum disorders require special dietary management. If these cases are diagnosed at an early stage, they can be helped through diet.

Adolescent↗

PubMed2004

Localization of white matter volume increase in autism and developmental language disorder.

Increased brain volume in autism appears to be driven mainly by an unexplained white matter enlargement, and we have reported a similar phenomenon in developmental language disorder (DLD). Localization of this enlargement would strongly guide research into its cause, tissue basis, and functional implications. We utilized a white matter parcellation technique that divides cerebral white matter into an outer zone containing the radiate compartment and an inner zone containing sagittal and bridging system compartments. In both high-functioning autism and DLD, enlargement localized to the radiate white matter (all lobes in autism, all but parietal in DLD), whereas inner zone white matter compartments showed no volume differences from controls. Furthermore, in both autism and DLD, later or longer-myelinating regions showed greater volume increases over controls. Neither group showed cerebral cortex, corpus callosum, or internal capsule volume differences from control. Radiate white matter myelinates later than deep white matter; this pattern of enlargement thus is consistent with striking postnatal head circumference percentile increases reported in autism. These findings suggest an ongoing postnatal process in both autism and DLD that is probably intrinsic to white matter, that primarily affects intrahemispheric and corticocortical connections, and that places these two disorders on the same spectrum.

Autistic Disorder↗

PubMed1997

Schizophrenia and autism considered as the products of an agnosic right shift gene.

Crow (1995a) has argued that schizophrenia is caused by a gene associated with the evolution of human language and cerebral specialisation. This paper suggests a mechanism for Crow's theory which requires only one new assumption for the right shift genetic model of handedness and cerebral dominance (Annett, 1978). The proposal is that the RS+ allele, whose normal function is to induce the left hemisphere to serve speech by impairing speech-related cortex in the right hemisphere, tends to lose its directional coding. It becomes agnosic (RS+ a) for right versus left and impairs the left or right hemisphere at random. Schizophrenia is likely to develop when the RS+ a gene is paired with a normal RS+ gene but only in the 50% of cases where both hemispheres are affected. In the 50% where RS+ a affects the right hemisphere, development is normal as in the RS+ RS+ genotype. The risks for schizophrenia in monozygotic and dizygotic twins and other relatives are as expected for 50% expression of a Mendelian gene which is paired with a particular allele, but not alternative alleles at the same locus. The frequency of homozygotes for the agnosic gene is about 4 in 10,000, the rate observed for autism. A random pattern of double hemisphere deficits would give scope for a range of developmental strengths and weaknesses as observed within the spectrum of autistic disorders. Tests of the model require brain-imaging studies sensitive to individual differences in hemisphere lateralisation and a search for a genetic locus with human and nonhuman primate alleles, together with a mutant of the human form with a frequency of about 2%.

Journal Article↗

PubMed2003

Disease susceptibility genes for autism.

Autism is a complex neurodevelopmental disorder characterized by impairment in social interaction accompanied by a delay or lack of language, restricted interests, stereotyped behavior, and repetitive movement. Genetic predisposition to autism is evident from family and twin studies, and heritability in idiopathic autism is estimated at over 90%. Frequency of the disorder is approximately 1:2000 with a male to female ratio of 4:1. Affected individuals look normal at birth, and the symptoms manifest at the first 2-3 years of life. The spectrum of clinical symptoms and the severity of the disorder are variable even among siblings. Family studies and several genome-wide linkage analyses support the hypothesis of complex inheritance with involvement of as many as 10-100 genes of moderate effect. Identification of genes responsible for the phenotype would help to understand the molecular mechanisms of the disorder. Several genes have been proposed to play a role in susceptibility to autism, and this paper will overview those genes and their potential role in the disorder.

Autistic Disorder↗

PubMed2006

Brief report: relative effectiveness of different home-based behavioral approaches to early teaching intervention.

The effectiveness of home-based early behavioral interventions for children (2:6-4:0 years old) with autistic spectrum disorders was studied over 9-10 months. Measures of autistic severity, intellectual, educational, and adaptive behavioral functioning were taken. There was no evidence of recovery from autism. High-intensity behavioral approaches (mean 30 h/week) produced greater gains than low-intensity programs (mean 12 h/week). Lovaas- and complete application of behavior analysis to schools approach-type interventions produced largest gains [similar to gains produced by longer-term clinic-based applied behavior analysis (ABA) programs]. Within the high-intensity groups, increased temporal input on the program was not associated with increased gains in the children. The results from clinic-based ABA trials were partially replicated on a home-based sample, using children with greater autistic and intellectual impairments.

Age Factors↗

PubMed2003

An epidemiological study on Japanese autism concerning routine childhood immunization history.

To assess the causal association of autism with measles, mumps, and rubella (MMR) vaccine versus that with monovalent measles, mumps, and rubella immunization, a 1:2 sex-adjusted logistic regression analysis was conducted using data on subjects who were growing up in the Tokyo area between 1988 and 1992. When MMR immunization was used as a reference, monovalent measles immunization (odds ratio [OR] = 5.33, 99% confidence interval [CI]: 1.03-27.74), non-mumps immunization (OR = 8, 99%CI: 1.33-48.2), and non-rubella immunization (OR = 8.57, 99%CI: 1.30-56.4) with development of autistic spectrum disorders (ASD) were significantly increased. These results suggest a decreased risk of developing ASD with MMR compared to monovalent antigens. However, our findings may reflect potential selection bias due to requiring written consent, possible delayed vaccination in suspected autism cases, and small sample size (case = 21). For the case group and the control group, immunization completeness rate of each antigen, regardless of the timing of immunization, was 90.5% versus 100% in measles, 42.9% versus 78.6% in mumps (P < 0.01), 52.3% versus 83.3% in rubella (P < 0.01), 14.3% versus 45.2% in varicella (P < 0.01), 100% versus 90.5% in polio>2, 100% versus 97.6% in Diphtheria (D), pertussis, and tetanus (T)>3, 85.7% versus 66.7% in DT, 95.2% versus 92.9% in BCG, and 52.4% versus 81.0% in Japanese encephalitis>3 (P<0.01). Only two case subjects and four control subjects received their measles, mumps, and rubella immunizations separately, suggesting that few Japanese parents might have had concerns about the safety of MMR vaccine. A nation-wide study would be a practical measure to scientifically judge the safety of MMR and other routine childhood immunizations.

Autistic Disorder↗

PubMed2024

Expanding the phenotype and genotype spectrum of TAOK1 neurodevelopmental disorder and delineating TAOK2 neurodevelopmental disorder.

PURPOSE: The thousand and one kinase (TAOK) proteins are a group of serine/threonine-protein kinases involved in signaling pathways, cytoskeleton regulation, and neuronal development. TAOK1 variants are associated with a neurodevelopmental disorder (NDD) characterized by distinctive facial features, hypotonia, and feeding difficulties. TAOK2 variants have been reported to be associated with autism and early-onset obesity. However, a distinct TAOK2-NDD has not yet been delineated. METHODS: We retrospectively studied the clinical and genetic data of individuals recruited from several centers with TAOK1 and TAOK2 variants that were detected through exome and genome sequencing. RESULTS: We report 50 individuals with TAOK1 variants with associated phenotypes, including neurodevelopmental abnormalities (100%), macrocephaly (83%), and hypotonia (58%). We report male genital anomalies and hypoglycemia as novel phenotypes. Thirty-seven unique TAOK1 variants were identified. Most of the missense variants clustered in the protein kinase domain at residues that are intolerant to missense variation. We report 10 individuals with TAOK2 variants with associated phenotypes, including neurodevelopmental abnormalities (100%), macrocephaly (75%), autism (75%), and obesity (70%). CONCLUSION: We describe the largest cohort of TAOK1-NDD to date, to our knowledge, expanding its phenotype and genotype spectrum with 30 novel variants. We delineated the phenotype of a novel TAOK2-NDD associated with neurodevelopmental abnormalities, autism, macrocephaly, and obesity.

Humans↗

PubMed2005

Genetic linkage analysis of the X chromosome in autism, with emphasis on the fragile X region.

The higher prevalence of autism in males than in females suggests the possible involvement of the X chromosome. To test the hypothesis that there are mutations increasing susceptibility to autism on the X chromosome, and in particular the distal portion of the long arm that encompasses the FMRI and MECP2 loci, a genetic linkage study was performed. Twenty-two fragile X-negative families multiplex for autism and related disorders were used for the study. Linkage analysis, for markers in the Xq27-q28 region, using model-free likelihood-based analysis, produced a maximum MLOD of 1.7 for the narrowest diagnostic category of the typical autism/severe autism spectrum, and nonparametric analysis produced a maximum non-parametric lod (NPL) score of 2.1 for a broad phenotype diagnostic model. Thus, this study offers modest support for a susceptibility locus for autism within the Xq27-q28 region. Further genetic investigations of this region are warranted.

Autistic Disorder↗

PubMed1992

The validity of autistic spectrum disorders: a literature review.

The objective of this literature review is to assess the validity of autistic spectrum disorders (ASD). Twenty papers were identified that adequately investigated the internal or external validity of various subtypes of ASD. At least three groups can be distinguished from autism on clinical grounds; an Asperger syndrome subtype, and two atypical subtypes characterized by low IQ and high IQ. However, the evidence that these clinical distinctions carry inferences with respect to etiology, clinical course, and treatment is only suggestive. Nevertheless, the specification of several ASD subtypes might promote further research and resolve many of the nosologic issues with respect to the classification of pervasive developmental disorders (PDDs).

Autistic Disorder↗

PubMed2003

Climbing the symbolic ladder in the DIR model through floor time/interactive play.

The developmental, individual-difference, relationship-based model (DIR), a theoretical and applied framework for comprehensive intervention, examines the functional developmental capacities of children in the context of their unique biologically based processing profile and their family relationships and interactive patterns. As a functional approach, it uses the complex interactions between biology and experience to understand behavior and articulates the developmental capacities that provide the foundation for higher order symbolic thinking and relating. During spontaneous 'floor time' play sessions, adults follow the child's lead utilizing affectively toned interactions through gestures and words to move the child up the symbolic ladder by first establishing a foundation of shared attention, engagement, simple and complex gestures, and problem solving to usher the child into the world of ideas and abstract thinking. This process is illustrated by a case example of a young boy on the autism spectrum interacting with his father during 'floor time' over a 3 year period.

Adult↗

PubMed2003

Understanding autism: insights from mind and brain.

Autism is a developmental disorder characterized by impaired social interaction and communication as well as repetitive behaviours and restricted interests. The consequences of this disorder for everyday life adaptation are extremely variable. The general public is now more aware of the high prevalence of this lifelong disorder, with ca. 0.6% of the population being affected. However, the signs and symptoms of autism are still puzzling. Since a biological basis of autism was accepted, approaches from developmental cognitive neuroscience have been applied to further our understanding of the autism spectrum. The study of the behavioural and underlying cognitive deficits in autism has advanced ahead of the study of the underlying brain abnormalities and of the putative genetic mechanisms. However, advances in these fields are expected as methodological difficulties are overcome. In this paper, recent developments in the field of autism are outlined. In particular, we review the findings of the three main neuro-cognitive theories of autism: theory-of-mind deficit, weak central coherence and executive dysfunction.

Autistic Disorder↗

PubMed2004

MECP2 structural and 3'-UTR variants in schizophrenia, autism and other psychiatric diseases: a possible association with autism.

Mutations in the gene coding for methyl-CpG-binding protein 2 (MECP2) cause Rett syndrome (RTT) and have also been reported in a number of X-linked mental retardation syndromes. Furthermore, putative mutations recently have been described in a few autistic patients and a boy with language disorder and schizophrenia. In this study, DNA samples from individuals with schizophrenia and other psychiatric diseases were scanned in order to explore whether the phenotypic spectrum of mutations in the MECP2 gene can extend beyond the traditional diagnoses of RTT in females and severe neonatal encephalopathy in males. The coding regions, adjacent splicing junctions, and highly conserved segments of the 3'-untranslated region (3'-UTR) were examined in 214 patients, including 106 with schizophrenia, 24 with autism, and 84 patients with other psychiatric diseases by detection of virtually all mutations-single strand conformation polymorphism (SSCP) (DOVAM-S). To our knowledge, this is the first analysis of variants in conserved regions of the 3'-UTR of this gene. A total of 5.2 kb per haploid gene was analyzed (1.5 Mb for 214 patients). A higher frequency of missense and 3'-UTR variants was found in autism. One missense and two 3'-UTR variants were found in 24 patients with autism versus one patient with a missense change in 144 ethnically similar individuals without autism (P = 0.009). These mutations suggest that a possible association between MECP2 mutations and autism may warrant further study.

3' Untranslated Regions↗

PubMed1999

Social and nonsocial factors in the Childhood Autism Rating Scale.

The Childhood Autism Rating Scale (CARS) was factor analyzed to determine if distinct and independent "subgroups" of symptoms could be derived, which would be consistent with the current multidimensional theory and nosology for autism. To address this issue, the CARS was factor analyzed for a sample of 90 children with diagnoses of either autism or PDDNOS, based on DSM-III-R diagnostic criteria. Five factors emerged: Social Communication, Emotional Reactivity, Social Orienting, Cognitive and Behavioral Consistency, and Odd Sensory Exploration. Factor-based scales were created. These factor-based scales were demonstrated to distinguish subjects with autism from subjects with PDDNOS and nonautistic subjects. Factor-based scores were examined to determine the degree to which they were associated with individual differences (such as age, IQ, gender, history of regression, and history of abnormal EEGs) among children with pervasive developmental disorders (PDDs). The application of these distinct and independent factors may have important clinical and research implications. The generation of factor-based scales may provide information on the nature of the individual differences that are thought to be present among children with autism. Additionally, the use of factor-based scale scores may increase the sensitivity of the CARS for identifying younger and/or higher functioning individuals within the PDD spectrum.

Analysis of Variance↗

PubMedDate not supplied

Infantile autism: an occasional manifestation of fragile (X) mental retardation.

Classical infantile autism occurs more frequently in males and has recently been noted in patients with the fragile (X) form of X-linked mental retardation (XLMR). In order to better understand this association and to determine whether fra(X) XLMR could account for the excess of autistic males, we investigated a group of institutionalized severely handicapped adults, 33 males and eight females, who were diagnosed as autistic using the DSM III diagnostic criteria of infantile autism. Chromosome studies using FUdR showed that three of the males had the Xq27 fragile site. We confirmed the association of autism and fra(X) XLMR, and showed that this extreme form of behaviour is part of the spectrum seen in the Martin-Bell syndrome. Two of the three autistic males with the Xq27 fragile site had a history of birth insults, which in combination with developmental deficits due to the fragile X gene, might have led to the behavioural disorder. Even though the fragile X cannot account for the excess of males with classical autism, it is an important X-linked factor in its cause. The diagnosis can allow more accurate counselling for this subset of autistic males.

Adult↗

PubMed2005

Novel treatments for autistic spectrum disorders.

In no area of developmental pediatric practice is there more controversy regarding the choice of treatment than related to children with autistic spectrum disorders (ASD). Complementary and alternative medical therapies (CAM) are often elected because they are perceived as treating the cause of symptoms rather than the symptoms themselves. CAM used for autism can be divided by proposed mechanism: immune modulation, gastrointestinal, supplements that affect neurotransmitter function, and nonbiologic intervention. Secretin as a therapy for autism is discussed as an example of how a clinical observation rapidly grew to a widespread treatment before well-designed studies demonstrated absence of effect. The plausibility for behavioral effect was not substantiated by clinical studies. CAM used for treatment of autism is examined in terms of rationale, evidence of efficacy, side effects, and additional commentary. Families and clinicians need access to well-designed clinical evidence to assist them in choice of therapies.

Anti-Bacterial Agents↗

PubMed2005

Autistic-spectrum disorders: lessons from neuroimaging.

Autistic-spectrum disorder is approximately half as common as schizophrenia but its cause remains unknown. Recent studies have begun to clarify the underlying neuroanatomical abnormalities and brain-behaviour relationships in autism. In the past decade, great advances have been made in our understanding of the neurobiological basis of autism.

Autistic Disorder↗

PubMed2002

Double-blind, placebo-controlled study of L-carnosine supplementation in children with autistic spectrum disorders.

L-Carnosine, a dipeptide, can enhance frontal lobe function or be neuroprotective. It can also correlate with gamma-aminobutyric acid (GABA)-homocarnosine interaction, with possible anticonvulsive effects. We investigated 31 children with autistic spectrum disorders in an 8-week, double-blinded study to determine if 800 mg L-carnosine daily would result in observable changes versus placebo. Outcome measures were the Childhood Autism Rating Scale, the Gilliam Autism Rating Scale, the Expressive and Receptive One-Word Picture Vocabulary tests, and Clinical Global Impressions of Change. Children on placebo did not show statistically significant changes. After 8 weeks on L-carnosine, children showed statistically significant improvements on the Gilliam Autism Rating Scale (total score and the Behavior, Socialization, and Communication subscales) and the Receptive One-Word Picture Vocabulary test (all P < .05). Improved trends were noted on other outcome measures. Although the mechanism of action of L-carnosine is not well understood, it may enhance neurologic function, perhaps in the enterorhinal or temporal cortex.

Autistic Disorder↗

PubMed2004

Regression and word loss in autistic spectrum disorders.

BACKGROUND: For many years, researchers and clinicians have described parent reports of an unusual developmental phenomenon in a substantial minority of children with Autistic Spectrum Disorders (ASD), the acquisition and then loss of communication skills during the second year of life. METHODS: As part of a longitudinal study of 110 children referred for assessments of possible autism at age 2 years or younger, 21 developmentally delayed children and 33 typically developing controls, 19 children were described by their parents at age 2 as having gained and lost spontaneous, meaningful words, and 12 children as having a history of less specific loss of imitated words or nonword vocalizations. A battery of diagnostic and cognitive tasks was administered to all children at study entrance, at ages 3 (for the referral children only) and 4 or 5 (for referral and developmentally delayed children). RESULTS: Results indicated that the acquisition of a small number of spontaneous words used meaningfully and consistently followed by loss of all words, often associated with other social changes, was unique to children diagnosed at 5 years with ASD. Few differences, besides those that defined the pattern of word loss, emerged between children with ASD with and without word loss. Loss of less specific, nonword vocalizations was associated with cognitive delay, with or without autism. CONCLUSIONS: Word loss is a reliably identifiable phenomenon in early childhood that appears to be unique, but not universal to, ASD. Histories and outcome of children with word loss were not in keeping with a sudden change from normal to abnormal functioning, but did suggest that this type of loss in the second year of life may be a useful 'red flag' for ASD in a significant minority of cases.

Autistic Disorder↗