David J. Posey

Autism genome-wide copy number variation reveals ubiquitin and neuronal genes

Autism spectrum disorders (ASDs) are childhood neurodevelopmental disorders with complex genetic origins. Previous studies focusing on candidate genes or genomic regions have identified several copy number variations (CNVs) that are associated with an increased risk of ASDs. Here we present the results from a whole-genome CNV study on a cohort of 859 ASD cases and 1,409 healthy children of European ancestry who were genotyped with ∼550,000 single nucleotide polymorphism markers, in an attempt to comprehensively identify CNVs conferring susceptibility to ASDs. Positive findings were evaluated in an independent cohort of 1,336 ASD cases and 1,110 controls of European ancestry. Besides previously reported ASD candidate genes, such as NRXN1 (ref. 10) and CNTN4 (refs 11, 12), several new susceptibility genes encoding neuronal cell-adhesion molecules, including NLGN1 and ASTN2, were enriched with CNVs in ASD cases compared to controls (P = 9.5 × 10-3). Furthermore, CNVs within or surrounding genes involved in the ubiquitin pathways, including UBE3A, PARK2, RFWD2 and FBXO40, were affected by CNVs not observed in controls (P = 3.3 × 10-3). We also identified duplications 55 kilobases upstream of complementary DNA AK123120 (P = 3.6 × 10-6). Although these variants may be individually rare, they target genes involved in neuronal cell-adhesion or ubiquitin degradation, indicating that these two important gene networks expressed within the central nervous system may contribute to the genetic susceptibility of ASD.

Repetitive thoughts and behavior in pervasive developmental disorders: treatment with serotonin reuptake inhibitors.

Repetitive thoughts and behavior are considered integral and core components of autistic disorder. Results from recent studies suggest that the types of repetitive thoughts and behavior of adults with autism and those with obsessive-compulsive disorder (OCD) may be different. Serotonin reuptake inhibitors (SRIs), the primary drug treatment for patients with OCD, may reduce the repetitive phenomena of some autistic patients. Two controlled studies of the nonselective SRI clomipramine have shown the drug to be more efficacious than the relatively selective norepinephrine reuptake inhibitor desipramine and placebo in children with autism. One controlled study of the selective SRI fluvoxamine found it to be significantly better than placebo for reducing repetitive phenomena and aggression in adults with autistic disorder. Additional research is needed.

High nitric oxide production in autistic disorder: a possible role for interferon-γ

BACKGROUND Neuroimmune regulation abnormalities have been implicated in the pathophysiology of autistic disorder. Nitric oxide (NO) is involved in immune reactivity and is known to affect brain neurodevelopmental processes. Recent evidence indicates that NO, and cytokines involved in NO production, may be high in children with autism. The purpose of this study was to verify that plasma NO is high in children with autism and determine whether this elevation is related to plasma levels of cytokines involved in NO production. METHODS The metabolites of NO, nitrite, and nitrate (NOx), along with the cytokines interferon-gamma (IFN-gamma), tumor necrosis factor-alpha, and interleukin-1beta, were measured in plasma of 29 children with autism (mean age +/- SD = 6.1 +/- 2.8 years) and 27 age- and gender-matched healthy comparison subjects using commercially available assay kits. RESULTS Plasma levels of NOx were significantly higher in the autistic subjects (p =.006); plasma levels of the cytokines did not differ between groups. NOx and IFN-gamma levels were positively correlated in the autistic subjects (r =.51; p =.005). CONCLUSIONS These results confirm that plasma NO is high in some children with autism and suggest that this elevation may be related to IFN-gamma activity.

Gastrointestinal Symptoms in a Sample of Children with Pervasive Developmental Disorders

Objective To evaluate gastrointestinal (GI) problems in a large, well-characterized sample of children with pervasive developmental disorders (PDDs). Methods One hundred seventy two children entering one of two trials conducted by the Research Units on Pediatric Psychopharmacology (RUPP) Autism Network were assessed comprehensively prior to starting treatment and classified with regard to GI symptoms. Results Thirty nine (22.7%) were positive for GI problems, primarily constipation and diarrhea. Those with GI problems were no different from subjects without GI problems in demographic characteristics, measures of adaptive functioning, or autism symptom severity. Compared to children without GI problems, those with GI problems showed greater symptom severity on measures of irritability, anxiety, and social withdrawal. Those with GI problems were also less likely to respond to treatment.

Effects of Short- and Long-Term Risperidone Treatment on Prolactin Levels in Children with Autism

BACKGROUND The effects of short- and long-term risperidone treatment on serum prolactin were assessed in children and adolescents with autism. METHODS Patients with autism (N = 101, 5-17 years of age) were randomized to an 8-week trial of risperidone or placebo and 63 then took part in a 4-month open-label follow-up phase. Serum samples were obtained at Baseline and Week-8 (N = 78), and at 6-month (N = 43) and 22-month (N = 30) follow-up. Serum prolactin was determined by immunoradiometric assay; dopamine type-2 receptor (DRD2) polymorphisms were genotyped. RESULTS Baseline prolactin levels were similar in the risperidone (N = 42) and placebo (N = 36) groups (9.3 +/- 7.5 and 9.3 +/- 7.6 ng/ml, respectively). After 8 weeks of risperidone, prolactin increased to 39.0 +/- 19.2 ng/ml, compared with 10.1 +/- 8.8 ng/ml for placebo (p < .0001). Prolactin levels were also significantly increased at 6 months (32.4 +/- 17.8 ng/ml; N = 43, p < .0001) and at 22 months (N = 30, 25.3 +/- 15.6 ng/ml, p < .0001). Prolactin levels were not associated with adverse effects and DRD2 alleles (Taq1A, -141C Ins/Del, C957T) did not significantly influence baseline levels or risperidone-induced increases in prolactin. CONCLUSIONS Risperidone treatment was associated with two- to four-fold mean increases in serum prolactin in children with autism. Although risperidone-induced increases tended to diminish with time, further research on the consequences of long-term prolactin elevations in children and adolescents is needed.

Validity of the Autism Diagnostic Interview-Revised

The factor structure, internal consistency, and convergent validity of the Autism Diagnostic Interview-Revised (ADI-R) algorithm items were examined in a sample of 226 youngsters with pervasive developmental disabilities. Exploratory factor analyses indicated a three-factor solution closely resembling the original algorithm and explaining 38% of the variance, with one significant discrepancy: Unlike the algorithm, all nonverbal communication items were associated with the Social factor. Internal consistencies of domain scores ranged from .54 to .84. Correlations between ADI-R domain and total scores and instruments assessing adaptive behavior, psychopathology, and autism were examined. They indicated some similarities between constructs, but also that the ADI-R measures autism in a unique fashion.

Antipsychotics in the treatment of autism

Atypical antipsychotics have become indispensable in the treatment of a variety of symptoms in autism. They are frequently used to treat irritability and associated behaviors including aggression and self injury. They may also be efficacious for hyperactivity and stereotyped behavior. This review presents the rationale for the use of this drug class in autism and reviews the most important studies published on this topic to date. Significant adverse effects, including weight gain and the possibility of tardive dyskinesia, are reviewed. Future research directions are discussed.

Assessment in Multisite Randomized Clinical Trials of Patients with Autistic Disorder: The Autism RUPP Network

Assessment of autistic disorder (autism) symptoms, primary and secondary, poses more challenging problems than ordinarily found in multisite randomized clinical trial (RCT) assessments. For example, subjects may be uncommunicative and extremely heterogeneous in problem presentation, and current pharmacological treatments are not likely to alter most core features of autism. The Autism Research Units on Pediatric Psychopharmacology (RUPP Autism Network) resolved some of these problems during the design of a risperidone RCT in children/adolescents. The inappropriateness of the usual anchors for a Clinical Global Impression of Severity (CGI-S) was resolved by defining uncomplicated autism without secondary symptoms as a CGI-S of 3, mildly ill. The communication problems, compromising use of the patient as an informant, were addressed by several strategies, including careful questioning of care providers, rating scales, laboratory tests, and physical exams. The broad subject heterogeneity requires outcome measures sensitive to individual change over a wide spectrum of treatment response and side effects. The problems of neuropsychologically testing nonverbal, lower functioning, sometimes noncompliant subjects requires careful instrument selection/adaptation and flexible administration techniques. The problems of assessing low-end IQs, neglected by most standardized test developers, was resolved by an algorithm of test hierarchy. Scarcity of other autism-adapted cognitive and neuropsychological tests and lack of standardization required development of a new, specially adapted battery. Reliability on the Autism Diagnostic Interview (currently the most valid diagnostic instrument) and other clinician instruments required extensive cross-site training (in-person, videotape, and teleconference sessions). Definition of a treatment responder required focus on individually relevant target symptoms, synthesis of possible modest improvements in many domains, and acceptance of attainable though imperfect goals. The assessment strategy developed is implemented in a RCT of risperidone (McDougle et al., 2000) for which the design and other methodological challenges are described elsewhere (Scahill et al., 2000). Some of these problems and solutions are partially shared with RCTs of other treatments and other disorders.

Guanfacine Treatment of Hyperactivity and Inattention in Pervasive Developmental Disorders: A Retrospective Analysis of 80 Cases

OBJECTIVE The aim of this study was to retrospectively review a large sample of children and adolescents with pervasive developmental disorders (PDDs) treated with open-label guanfacine in order to gather preliminary data as to its effectiveness and safety. METHOD Eighty (80) subjects with PDDs (10 females, 70 males) (mean +/- SD age = 7.7 +/- 3.5 years, range 3-18 years) were treated with guanfacine within an academic specialty clinic. Charts were reviewed to determine the response of specific target symptoms, including hyperactivity, inattention, and impulsivity. The relationship between treatment response and age, diagnosis, level of cognitive impairment, and symptom severity was determined. Adverse effects were also evaluated. RESULTS Guanfacine (mean daily dose = 2.6 +/- 1.7 mg, range 0.25-9 mg; mean duration of treatment = 334 +/- 374 days, range 7-1776 days) treatment was effective in 19 of 80 (23.8%) subjects. Subjects with PDD not otherwise specified (11 of 28 responders; 39.3%) and Aspergers disorder (2 of 6 responders; 33.3%) showed a greater rate of global response than those with autistic disorder (6 of 46 responders; 13.0 %). There was a trend for subjects without comorbid mental retardation (9 of 24 subjects; 37.5%) to respond at a greater rate than those with mental retardation (10 of 56 subjects; 17.9%). Symptom improvement was seen in hyperactivity, inattention, insomnia, and tics. Guanfacine was well tolerated, and did not lead to significant changes in blood pressure or heart rate. CONCLUSIONS Guanfacine may have a role in the treatment of hyperactivity and inattention occurring in some persons with PDDs. Further studies are needed to determine its efficacy in this population.

Weight Gain Associated with Atypical Antipsychotic Use in Children and Adolescents

Atypical antipsychotics are increasingly prescribed to children and adolescents with neuropsychiatric disorders. Although their profile of potent antagonism at specific serotonin and dopamine receptors offers certain advantages compared with typical antipsychotics, their use has been associated with various adverse effects, including significant weight gain. This adverse effect is of particular concern in children and adolescents, secondary to the immediate and long-term health risks associated with weight gain, including obesity, diabetes mellitus, and hyperlipidemia. Indeed, from 1963 to 1991, the prevalence of obesity has approximately doubled in youth. Prior to selecting an atypical antipsychotic, a detailed review of the predictors of weight gain is necessary for every child and adolescent. Published data suggest that clozapine and olanzapine are associated with considerable weight gain, whereas risperidone and quetiapine have a moderate risk. Alternatively, ziprasidone and aripiprazole may exhibit a low risk for this adverse effect. Whereas behavioral and pharmacologic measures are available to manage weight gain associated with atypical antipsychotics, research is needed to establish more effective and safe interventions for this adverse effect in children and adolescents.