Structural variation of chromosomes in autism spectrum disorder.

Structural variation (copy number variation [CNV] including deletion and duplication, translocation, inversion) of chromosomes has been identified in some individuals with autism spectrum disorder (ASD), but the full etiologic role is unknown. We performed genome-wide assessment for structural abnormalities in 427 unrelated ASD cases via single-nucleotide polymorphism microarrays and karyotyping. With microarrays, we discovered 277 unbalanced CNVs in 44% of ASD families not present in 500 controls (and re-examined in another 1152 controls). Karyotyping detected additional balanced changes. Although most variants were inherited, we found a total of 27 cases with de novo alterations, and in three (11%) of these individuals, two or more new variants were observed. De novo CNVs were found in approximately 7% and approximately 2% of idiopathic families having one child, or two or more ASD siblings, respectively. We also detected 13 loci with recurrent/overlapping CNV in unrelated cases, and at these sites, deletions and duplications affecting the same gene(s) in different individuals and sometimes in asymptomatic carriers were also found. Notwithstanding complexities, our results further implicate the SHANK3-NLGN4-NRXN1 postsynaptic density genes and also identify novel loci at DPP6-DPP10-PCDH9 (synapse complex), ANKRD11, DPYD, PTCHD1, 15q24, among others, for a role in ASD susceptibility. Our most compelling result discovered CNV at 16p11.2 (p = 0.002) (with characteristics of a genomic disorder) at approximately 1% frequency. Some of the ASD regions were also common to mental retardation loci. Structural variants were found in sufficiently high frequency influencing ASD to suggest that cytogenetic and microarray analyses be considered in routine clinical workup.

Long-term effects of risperidone in children with autism spectrum disorders: a placebo discontinuation study.

OBJECTIVE: The short-term benefit of risperidone in ameliorating severe disruptive behavior in pediatric patients with autism spectrum disorders is well established; however, only one placebo-controlled, long-term study of efficacy is available. METHOD: Thirty-six children with an autism spectrum disorder (5-17 years old) accompanied by severe tantrums, aggression, or self-injurious behavior, started 8-week open-label treatment with risperidone. Responders (n = 26) continued treatment for another 16 weeks, followed by a double-blind discontinuation (n = 24; two patients discontinued treatment because of weight gain) consisting of either 3 weeks of taper and 5 weeks of placebo only or continuing use of risperidone. Relapse was defined as a significant deterioration of symptoms based on clinical judgment and a parent questionnaire. RESULTS: Risperidone was superior to placebo in preventing relapse: this occurred in 3 of 12 patients continuing on risperidone versus 8 of 12 who switched to placebo (p = .049). Weight gain, increased appetite, anxiety, and fatigue were the most frequently reported side effects. CONCLUSIONS: This study indicates the effectiveness of risperidone during a period of several months, reducing disruptive behavior in about half of the children with autism spectrum disorders. The results provide a rationale for the continuing use of risperidone beyond 6 months, although considerable weight gain can limit the use of this agent.

Deficits in motor control processes involved in production of graphic movements of children with attention-deficit-hyperactivity disorder.

This study aimed to investigate whether two distinct motor control processes, i.e. motor planning and parameter setting, were impaired in children with attention-deficit-hyperactivity disorder (ADHD). An experiment was designed in which children copied figures of increasing complexity under increasing accuracy levels on a digitizer. Sixteen children with ADHD (11 males, 5 females; mean age 8 y 4 mo, SD 1 y 1 mo) and 16 comparison children, without impairment, matched for age and sex participated. ADHD was diagnosed by a psychiatrist following the criteria of the DSM-V. Only children with IQ scores greater than 80 were included. Across all graphic tasks, children with ADHD made slower, inaccurate strokes with relatively high axial pen force compared with the comparison group. No evidence was found for a deficit in motor planning, but parameter setting appeared to be deficient as the ADHD group made less accurate strokes when accuracy demands increased.

Serotonin transporter intron 2 polymorphism associated with rigid-compulsive behaviors in Dutch individuals with pervasive developmental disorder.

Two putatively functional polymorphisms of the serotonin transporter gene (HTT, SLC6A4) were examined for associations with risk for pervasive developmental disorders (PDDs) and specific autism phenotypes. Dutch patients diagnosed with PDD (N = 125, age range 5-20 years, DSM-IV-TR based criteria, ADI-R and ADOS behavioral assessments) and their parents (N = 230) were genotyped for promoter ins/del (5-HTTLPR) and intron 2 variable number of tandem repeats (VNTR) alleles. Using the transmission disequilibrium test (TDT), no disorder-specific preferential transmission of promoter (long and short) or intron 2 (10- and 12-repeat) alleles was observed. However, multivariate analysis of continuous autism-related behavioral measures revealed that subjects with intron 2 12/12 genotype were significantly more impaired in the rigid-compulsive domain (P = 0.008). Quantitative TDT (QTDT) analysis also showed significant association of the intron 2 VNTR 12-repeat allele with rigid-compulsive behavior (P = 0.015). These results suggest that intron 2 VNTR alleles or nearby polymorphisms in linkage disequilibrium may play a role in specific aspects of the behavioral phenotype of autism.