Publications by authors named "Cees E J Ketelaars"

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).

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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.

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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).

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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.

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