1. {{Prevalence of autism spectrum disorders – Autism and Developmental Disabilities Monitoring Network, United States, 2006}}. {MMWR Surveill Summ}. 2009 Dec 18;58(10):1-20.
PROBLEM/CONDITION: Autism spectrum disorders (ASDs) are a group of developmental disabilities characterized by atypical development in socialization, communication, and behavior. ASDs typically are apparent before age 3 years, with associated impairments affecting multiple areas of a person’s life. Because no biologic marker exists for ASDs, identification is made by professionals who evaluate a child’s developmental progress to identify the presence of developmental disorders. REPORTING PERIOD: 2006. METHODS: Earlier surveillance efforts indicated that age 8 years is a reasonable index age at which to monitor peak prevalence. The identified prevalence of ASDs in U.S. children aged 8 years was estimated through a systematic retrospective review of evaluation records in multiple sites participating in the Autism and Developmental Disabilities Monitoring (ADDM) Network. Data were collected from existing records in 11 ADDM Network sites (areas of Alabama, Arizona, Colorado, Florida, Georgia, Maryland, Missouri, North Carolina, Pennsylvania, South Carolina, and Wisconsin) for 2006. To analyze changes in identified ASD prevalence, CDC compared the 2006 data with data collected from 10 sites (all sites noted above except Florida) in 2002. Children aged 8 years with a notation of an ASD or descriptions consistent with an ASD were identified through screening and abstraction of existing health and education records containing professional assessments of the child’s developmental progress at health-care or education facilities. Children aged 8 years whose parent(s) or legal guardian(s) resided in the respective areas in 2006 met the case definition for an ASD if their records documented behaviors consistent with the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revision (DSM-IV-TR) criteria for autistic disorder, pervasive developmental disorder–not otherwise specified (PDD NOS), or Asperger disorder. Presence of an identified ASD was determined through a review of data abstracted from developmental evaluation records by trained clinician reviewers. RESULTS: For the 2006 surveillance year, 2,757 (0.9%) of 307,790 children aged 8 years residing in the 11 ADDM sites were identified as having an ASD, indicating an overall average prevalence of 9.0 per 1,000 population (95% confidence interval [CI] = 8.6-9.3). ASD prevalence per 1,000 children aged 8 years ranged from 4.2 in Florida to 12.1 in Arizona and Missouri, with prevalence for the majority of sites ranging between 7.6 and 10.4. For 2006, ASD prevalence was significantly lower in Florida (p<0.001) and Alabama (p<0.05) and higher in Arizona and Missouri (p<0.05) than in all other sites. The ratio of males to females ranged from 3.2:1 in Alabama to 7.6:1 in Florida. ASD prevalence varied by type of ascertainment source, with higher average prevalence in sites with access to health and education records (10.0) compared with sites with health records only (7.5). Although parental or professional concerns regarding development before age 36 months were noted in the evaluation records of the majority of children who were identified as having an ASD, the median age of earliest documented ASD diagnosis was much later (range: 41 months [Florida]-60 months [Colorado]). Of 10 sites that collected data for both the 2002 and 2006 surveillance years, nine observed an increase in ASD prevalence (range: 27%-95% increase; p<0.01), with increases among males in all sites and among females in four of 11 sites, and variation among other subgroups. INTERPRETATION: In 2006, on average, approximately 1% or one child in every 110 in the 11 ADDM sites was classified as having an ASD (approximate range: 1:80-1:240 children [males: 1:70; females: 1:315]). The average prevalence of ASDs identified among children aged 8 years increased 57% in 10 sites from the 2002 to the 2006 ADDM surveillance year. Although improved ascertainment accounts for some of the prevalence increases documented in the ADDM sites, a true increase in the risk for children to develop ASD symptoms cannot be ruled out. On average, although delays in identification persisted, ASDs were being diagnosed by community professionals at earlier ages in 2006 than in 2002. PUBLIC HEALTH ACTIONS: These results indicate an increased prevalence of identified ASDs among U.S. children aged 8 years and underscore the need to regard ASDs as an urgent public health concern. Continued monitoring is needed to document and understand changes over time, including the multiple ascertainment and potential risk factors likely to be contributing. Research is needed to ascertain the factors that put certain persons at risk, and concerted efforts are essential to provide support for persons with ASDs, their families, and communities to improve long-term outcome.
2. Groen WB, Tesink C, Petersson KM, van Berkum J, van der Gaag RJ, Hagoort P, Buitelaar JK. {{Semantic, Factual, and Social Language Comprehension in Adolescents with Autism: An FMRI Study}}. {Cereb Cortex}. 2009 Dec 16.
Language in high-functioning autism is characterized by pragmatic and semantic deficits, and people with autism have a reduced tendency to integrate information. Because the left and right inferior frontal (LIF and RIF) regions are implicated with integration of speaker information, world knowledge, and semantic knowledge, we hypothesized that abnormal functioning of the LIF and RIF regions might contribute to pragmatic and semantic language deficits in autism. Brain activation of sixteen 12- to 18-year-old, high-functioning autistic participants was measured with functional magnetic resonance imaging during sentence comprehension and compared with that of twenty-six matched controls. The content of the pragmatic sentence was congruent or incongruent with respect to the speaker characteristics (male/female, child/adult, and upper class/lower class). The semantic- and world-knowledge sentences were congruent or incongruent with respect to semantic expectancies and factual expectancies about the world, respectively. In the semantic-knowledge and world-knowledge condition, activation of the LIF region did not differ between groups. In sentences that required integration of speaker information, the autism group showed abnormally reduced activation of the LIF region. The results suggest that people with autism may recruit the LIF region in a different manner in tasks that demand integration of social information.
3. James WH. {{A potential cause of the reported increase in rates of autism}}. {Int J Epidemiol}. 2009 Dec 18.
4. Narayan P, Dragunow M. {{Pharmacology of epigenetics in brain disorders}}. {Br J Pharmacol}. 2009 Dec 15.
Epigenetics is a rapidly growing field and holds great promise for a range of human diseases, including brain disorders such as Rett syndrome, anxiety and depressive disorders, schizophrenia, Alzheimer disease and Huntington disease. This review is concerned with the pharmacology of epigenetics to treat disorders of the epigenome whether induced developmentally or manifested/acquired later in life. In particular, we will focus on brain disorders and their treatment by drugs that modify the epigenome. While the use of DNA methyl transferase inhibitors and histone deacetylase inhibitors in in vitro and in vivo models have demonstrated improvements in disease-related deficits, clinical trials in humans have been less promising. We will address recent advances in our understanding of the complexity of the epigenome with its many molecular players, and discuss evidence for a compromised epigenome in the context of an ageing or diseased brain. We will also draw on examples of species differences that may exist between humans and model systems, emphasizing the need for more robust pre-clinical testing. Finally, we will discuss fundamental issues to be considered in study design when targeting the epigenome.
5. Sakurai T, Ramoz N, Barreto M, Gazdoiu M, Takahashi N, Gertner M, Dorr N, Sosa MA, Gasperi RD, Perez G, Schmeidler J, Mitropoulou V, Le HC, Lupu M, Hof PR, Elder GA, Buxbaum JD. {{Slc25a12 Disruption Alters Myelination and Neurofilaments: A Model for a Hypomyelination Syndrome and Childhood Neurodevelopmental Disorders}}. {Biol Psychiatry}. 2009 Dec 14.
BACKGROUND: SLC25A12, a susceptibility gene for autism spectrum disorders that is mutated in a neurodevelopmental syndrome, encodes a mitochondrial aspartate-glutamate carrier (aspartate-glutamate carrier isoform 1 [AGC1]). AGC1 is an important component of the malate/aspartate shuttle, a crucial system supporting oxidative phosphorylation and adenosine triphosphate production. METHODS: We characterized mice with a disruption of the Slc25a12 gene, followed by confirmatory in vitro studies. RESULTS: Slc25a12-knockout mice, which showed no AGC1 by immunoblotting, were born normally but displayed delayed development and died around 3 weeks after birth. In postnatal day 13 to 14 knockout brains, the brains were smaller with no obvious alteration in gross structure. However, we found a reduction in myelin basic protein (MBP)-positive fibers, consistent with a previous report. Furthermore, the neocortex of knockout mice contained abnormal neurofilamentous accumulations in neurons, suggesting defective axonal transport and/or neurodegeneration. Slice cultures prepared from knockout mice also showed a myelination defect, and reduction of Slc25a12 in rat primary oligodendrocytes led to a cell-autonomous reduction in MBP expression. Myelin deficits in slice cultures from knockout mice could be reversed by administration of pyruvate, indicating that reduction in AGC1 activity leads to reduced production of aspartate/N-acetylaspartate and/or alterations in the dihydronicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide(+) ratio, resulting in myelin defects. CONCLUSIONS: Our data implicate AGC1 activity in myelination and in neuronal structure and indicate that while loss of AGC1 leads to hypomyelination and neuronal changes, subtle alterations in AGC1 expression could affect brain development, contributing to increased autism susceptibility.
6. Wong VC, Kwan QK. {{Randomized Controlled Trial for Early Intervention for Autism: A Pilot Study of the Autism 1-2-3 Project}}. {J Autism Dev Disord}. 2009 Dec 18.
We piloted a 2-week « Autism-1-2-3 » early intervention for children with autism and their parents immediately after diagnosis that targeted at (1) eye contact, (2) gesture and (3) vocalization/words. Seventeen children were randomized into the Intervention (n = 9) and Control (n = 8) groups. Outcome measures included the Autism Diagnostic Observation Schedule, Ritvo-Freeman Real Life Rating Scale, Symbolic Play Test, and Parenting Stress Index. Children with autism improved in language/communication, reciprocal social interaction, and symbolic play. Parents perceived significant improvement in their children’s language, social interaction, and their own stress level. This intervention can serve as short-term training on communication and social interaction for children with autism, and reduce the stress of their parents during the long waiting time for public health services.
7. Wu DJ, Wang NJ, Driscoll J, Dorrani N, Liu D, Sigman M, Schanen NC. {{Autistic disorder associated with a paternally derived unbalanced translocation leading to duplication of chromosome 15pter-q13.2: a case report}}. {Mol Cytogenet}. 2009 Dec 18;2(1):27.
ABSTRACT: Autism spectrum disorders have been associated with maternally derived duplications that involve the imprinted region on the proximal long arm of chromosome 15. Here we describe a boy with a chromosome 15 duplication arising from a 3:1 segregation error of a paternally derived translocation between chromosome 15q13.2 and chromosome 9q34.12, which led to trisomy of chromosome 15pter-q13.2 and 9q34.12-qter.Using array comparative genome hybridization, we localized the breakpoints on both chromosomes and sequence homology suggests that the translocation arose from non-allelic homologous recombination involving the low copy repeats on chromosome 15. The child manifests many characteristics of the maternally-derived duplication chromosome 15 phenotype including developmental delays with cognitive impairment, autism, hypotonia and facial dysmorphisms with nominal overlap of the most general symptoms found in duplications of chromosome 9q34.This case suggests that biallelically expressed genes on proximal 15q contribute to the idic(15) autism phenotype.
8. Zhang JJ, Bao XH. {{ [Research progress of Rett syndrome causing gene MECP2–The structure, function and modulation of MECP2.]}}. {Beijing Da Xue Xue Bao}. 2009 Dec 18;41(6):712-5.
Rett syndrome (RTT), an X-linked dominant neurodevelopmental disorder characterized by regression of language, stereotype hand movement and loss of purposeful hand use, is primarily caused by mutation of menthyl-CpG-binding protein 2 (MECP2). The 76 kb human MECP2 is characterized by three salient features: a very large intron 2 (60 kb), an 8.5 kb 3′-UTR with highly conserved regions and different polyadenylation sites, and a 40 kb intergenic region separating MECP2 from the nearest upstream gene. There are two isoforms of MeCP2, MeCP2e1 and MeCP2e2. The differences between the two isoforms, the function of the 3′-UTR and the long-range cis-regulatory sequences in the intergenic region were extensively studied. In contrast to initial report, recent studies show that MeCP2 binds not only to methylated promoters and silence transcription, but also to the sites outside of genes containing only a few of CpG islands. Furthermore, MeCP2 can function as both an activator and a repressor of transcription.
