Biomedical subjects

Leila Ben Amor

Publications and source records attributed to Leila Ben Amor.

7 recordsLinked to original sources

PubMed2006

Dopamine transporter 3'-UTR VNTR genotype and ADHD: a pharmaco-behavioural genetic study with methylphenidate.

We sought to test the hypothesis that the variable number of tandem repeat (VNTR) polymorphism in the 3'-untranslated region (3'-UTR) of the SLC6A3 gene modulates behavior in children with ADHD and/or behavioral response to methylphenidate (MPH). One hundred and fifty-nine children with AHDH (6-12 years) were assessed with regard to the Conners' Global Index for parents (CGI-Parents) and teachers (CGI-Teachers) and the response of these behaviors to MPH (0.5 mg/kg/day) using a 2-week prospective within-subject (crossover) trial. Based on CGI-Parents, the profile of behavioral response to MPH as compared to placebo was not parallel in the three groups of children separated according to their genotype in the 3'-UTR VNTR polymorphism of SLC6A3, as indicated by a significant (p=0.017) genotype by treatment two-way interaction. Individuals having the 9/10 and 10/10 genotypes displayed a significant positive response to MPH as opposed to those homozygous for the 9-repeat allele. No genotype or genotype by treatment interaction was observed for CGI-Teachers. These findings support a role for the DAT gene 3'-UTR VNTR polymorphism in modulating the response of some behavioral dimensions to MPH in children with ADHD. They also suggest the presence of genetic heterogeneity that could be indexed by the quality of behavioral response to MPH.

3' Untranslated Regions↗

PubMed2006

Relationship between response to methylphenidate treatment in children with ADHD and psychopathology in their families.

OBJECTIVE: To compare the pattern of familial aggregation of psychopathology in children who are good responders (GR) to methylphenidate (MPH) versus those who are poor responders (PR). METHOD: A total of 118 clinically referred children ages 6 to 12 years, diagnosed with ADHD participated in a double-blind, placebo-controlled, randomized 2-week crossover trial of MPH from 1999 to 2004. A low dose of 0.5 mg/kg of body weight of MPH divided in two equal doses was used. Family history was obtained by interviewing at least one key historian relative of each subject using Family Interview for Genetic Studies. Information was collected on 342 first-degree and 1,151 second-degree relatives of children with attention-deficit/hyperactivity disorder. RESULTS: Forty-four subjects showed mild or no improvement (PR) and 74 showed moderate or very much improvement (GR) on MPH over placebo. First-degree relatives of GR subjects were at significantly higher risk of attention-deficit/hyperactivity disorder than the relatives of PR subjects (p<.05). Second-degree relatives of the GR were at significantly higher risk of antisocial personality disorder compared to the relatives of PR subjects (p<.05). CONCLUSIONS: The significantly higher presence of attention-deficit/hyperactivity disorder in the first-degree relatives and of antisocial personality disorder in the second-degree relatives of GR children suggests that this group may, at least partially, be distinct from the PR group on the basis of genetic determinants.

Attention Deficit Disorder with Hyperactivity↗

PubMed2006

Sleep and COMT polymorphism in ADHD children: preliminary actigraphic data.

OBJECTIVE: To examine whether COMT (catechol-O-methyltransferase) polymorphism modulates aspects of sleep in children diagnosed with attention-deficit/hyperactivity disorder (ADHD). METHOD: Nightly sleep actigraphic recordings during a double-blind, placebo-controlled, crossover clinical study (1 week of 0.5 mg/kg MPH; 1 week of placebo) were obtained for 34 children, 7.4 to 12 years old, diagnosed with ADHD (DSM-IV). Diagnosis was generated by the Diagnostic Interview Schedule for Children and was confirmed by multidisciplinary consensus. RESULTS: Children who were Val allele carriers had poorer sleep continuity compared with children with the Met-Met genotype while receiving a placebo and while receiving methylphenidate. CONCLUSIONS: The findings of the present study support the hypothesis that sleep disturbances in children with ADHD are related to the underlying pathophysiology of the disorder.

Attention Deficit Disorder with Hyperactivity↗

PubMed2006

COMT Val108/158Met gene variant, birth weight, and conduct disorder in children with ADHD.

OBJECTIVE: In a recent study, Thapar and colleagues reported that COMT "gene variant and birth weight predict early-onset antisocial behavior in children" with attention-deficit/hyperactivity disorder. We have attempted to replicate these findings in a group of ADHD children using a similar research design. METHOD: Children (n=191) between 6 and 12 years of age who were diagnosed with ADHD were included in the study. Conduct disorder was diagnosed according to DSM-IV criteria based on clinical evaluation and a structured interview (Diagnostic Interview Schedule for Children-IV). The mother's report on the child's birth weight was used in the analysis. Logistic regression analysis, with genotype and birth weight as independent variables and DSM-IV conduct disorder as the dependent variable, was conducted. RESULTS: No significant main effects of genotype and birth weight or interaction effects on conduct disorder were observed. CONCLUSION: In this sample of children diagnosed with ADHD, we find no association between the COMT ValMet gene variant, birth weight, and conduct disorder. Further investigations are required before using birth weight and COMT genotype as predictors of conduct disorder in children with attention-deficit/hyperactivity disorder, especially given the societal and legal ramifications of conduct disorder.

Birth Weight↗

PubMed2005

Perinatal complications in children with attention-deficit hyperactivity disorder and their unaffected siblings.

OBJECTIVES: Genetic and nonshared environmental factors (experienced by 1 family member to the exclusion of the others) have been strongly implicated in the causes of attention-deficit hyperactivity disorder (ADHD). Pregnancy, labour/delivery and neonatal complications (PLDNC) have often been associated with ADHD; however, no investigations aimed at delineating the shared or nonshared nature of these factors have been reported. We aimed to identify those elements of the PLDNC that are more likely to be of a nonshared nature. METHODS: We used an intrafamily study design, comparing the history of PLDNC between children diagnosed with ADHD, according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), and their unaffected siblings. Children with ADHD were recruited from the outpatient, day-treatment program of the Child Psychiatry Department, Douglas Hospital, Montreal. The unaffected sibling closest in age to the child with ADHD was used as a control. The history of PLDNC was assessed using the Kinney Medical and Gynecological Questionnaire and the McNeil-Sjostrom Scale for both children with ADHD and their siblings. Seventy children with ADHD along with 50 of their unaffected siblings agreed to participate in the study. Child Behavior Checklist (CBCL), Continuous Performance Test (CPT) and Restricted Academic Situation Scale (RASS) scores were also used as measures of ADHD symptoms in children with ADHD. RESULTS: The children with ADHD had significantly higher rates of neonatal complications compared with their unaffected siblings (F4,196 = 3.67, p < 0.006). Furthermore, neonatal complications in the children with ADHD were associated with worse CBCL total and externalizing scores and with poorer performance on the CPT. CONCLUSIONS: These results suggest that neonatal complications are probably a nonshared environmental risk factor that may be pathogenic in children with ADHD.

Adult↗

PubMed2004

Catechol-O-methyltransferase (COMT) Val108/158 Met polymorphism does not modulate executive function in children with ADHD.

BACKGROUND: An association has been observed between the catechol-O-methyltransferase (COMT) gene, the predominant means of catecholamine catabolism within the prefrontal cortex (PFC), and neuropsychological task performance in healthy and schizophrenic adults. Since several of the cognitive functions typically deficient in children with Attention Deficit Hyperactivity Disorder (ADHD) are mediated by prefrontal dopamine (DA) mechanisms, we investigated the relationship between a functional polymorphism of the COMT gene and neuropsychological task performance in these children. METHODS: The Val108/158 Met polymorphism of the COMT gene was genotyped in 118 children with ADHD (DSM-IV). The Wisconsin Card Sorting Test (WCST), Tower of London (TOL), and Self-Ordered Pointing Task (SOPT) were employed to evaluate executive functions. Neuropsychological task performance was compared across genotype groups using analysis of variance. RESULTS: ADHD children with the Val/Val, Val/Met and Met/Met genotypes were similar with regard to demographic and clinical characteristics. No genotype effects were observed for WCST standardized perseverative error scores [F2,97 = 0.67; p > 0.05], TOL standardized scores [F2,99 = 0.97; p > 0.05], and SOPT error scores [F2,108 = 0.62; p > 0.05]. CONCLUSIONS: Contrary to the observed association between WCST performance and the Val108/158 Met polymorphism of the COMT gene in both healthy and schizophrenic adults, this polymorphism does not appear to modulate executive functions in children with ADHD.

Amino Acid Substitution↗

PubMed2004

Actigraphic monitoring during sleep of children with ADHD on methylphenidate and placebo.

OBJECTIVE: Sleep disturbances appear as a comorbid condition in children with attention-deficit/hyperactivity disorder. The aim of this study was to investigate the relationship of activity levels during sleep and therapeutic response to methylphenidate (MPH). METHOD: Nightly sleep actigraphic recordings during a double-blind, placebo-controlled, crossover clinical study (1-week of 0.5 mg/kg MPH; 1-week of placebo) were obtained on 44 children, 6 to 12 years old, diagnosed with attention-deficit/hyperactivity disorder (DSM-IV). RESULTS: Significant (p <.005) differences between the conditions were found in several software-computed parameters: sleep onset latency (MPH, 39.3 minutes; placebo, 28.2 minutes), sleep efficiency (MPH, 78.0%; placebo, 80.4%), total sleep time (MPH, 7 hours; 57 minutes; placebo, 8 hours, 16 minutes). No significant differences on any of these measures were found among the 26 subjects who showed a moderate or large global improvement on MPH over placebo compared with 18 subjects who showed mild or no clinical improvement. CONCLUSIONS: MPH, given twice daily, induces a slight but significant sleep disturbance. Motor activity levels during sleep did not differentiate children who responded to MPH from those who did not respond. This suggests that responders to MPH treatment do not experience greater sleep disturbances than nonresponders, at least at the dose studied.

Attention Deficit Disorder with Hyperactivity↗