No evidence for preferential transmission of common valine allele of the Val66Met polymorphism of the brain-derived neurotrophic factor gene (BDNF) in ADHD

Attention deficit/hyperactivity disorder (ADHD) is a highly heritable common neurodevelopmental disorder with onset in childhood. A coding SNP (rs6265, Val66Met) of the brain-derived neurotrophic factor gene (BDNF) has recently been associated with ADHD. More specifically, paternal over-transmission of the common Val66 allele to affected children had been observed. We aimed to confirm these findings in a large, sufficiently powered, and well characterized German ADHD family sample. The Val66Met polymorphism of BDNF was genotyped in 294 families comprising one or more affected sibs (468 children). Contrary to previous reports, we did not observe over-transmission of the common Val66 allele, from either parent to affected children. We did not find support for an involvement of the Val66 allele of the Val66Met polymorphism of BDNF in the pathogenesis of ADHD in our sample.

Association of Parkinson's disease with symptoms of attention deficit hyperactivity disorder in childhood

Methylphenidate (MPH) is a centrally acting (psycho)stimulant which reversibly blocks the dopamine re-uptake transporter. At present MPH is one of the most frequently prescribed drugs for the symptomatic treatment of attention deficit hyperactivity disorder (ADHD). Although MPH has been in use for about 50 years, there is no information available concerning the long-term benefits and risks of medication. Based on experiments in rats it has been suggested that MPH treatment may affect the maturation of central dopaminergic systems and may be a risk factor for the development of Parkinson's disease (PD). The aim of the present case-control study was to gain information about (1) ADHD-like symptoms that may precede PD motor symptoms, and (2) the exposure to psychostimulants in childhood. We used a German short version of the Wender Utah Rating Scale (WURS-k, Retz-Junginger et al., 2002) which is a reliable measure for the retrospective diagnosis of childhood ADHD, and another questionnaire including a rating scale for symptoms of ADHD in childhood (Q-ADHD-Child) according to DSM-IV and ICD-10 criteria. A total of 92 patients with PD and 115 control subjects were enrolled in this study. Ninety-six percentage of PD patients (N = 88) completed the two rating scales. The data of these patients and of 88 randomly selected individuals of the controls were included for analysis. In the WURS-k, the PD group showed higher total scores compared to control subjects. In addition, we found increased scores in PD patients regarding the items attention deficit, hyperactivity and anxious and depressive symptoms, but not regarding impulsivity, oppositional behaviour and deficits in social adaptation. The results of the Q-ADHD-Child also showed increased scores in PD patients regarding attention deficit and hyperactivity. However, one cannot conclude that the PD patients enrolled in this study had suffered from childhood ADHD, since the average total WURS-k score of (14.4) was far below the cut-off score of 30 or higher which is considered to identify childhood ADHD. Finally, we found no evidence that PD patients had been exposed to psychostimulants such as MPH and amphetamine.

Weight gain associated with clozapine, olanzapine and risperidone in children and adolescents

The study was aimed at the evaluation of weight gain associated with atypical antipsychotics and its clinical risk factors in children and adolescents. Weight and body mass index (BMI) of initially hospitalised patients treated with clozapine (n = 15), olanzapine (n = 15), and risperidone (n = 15) were prospectively monitored on a weekly basis for the first 6 weeks. Different clinical risk factors were tested for their association with weight gain in the three groups. All three groups experienced significant weight gain between baseline and endpoint (p < 0.0001). For all weight measures, planned comparisons were all significant between olanzapine vs. clozapine and risperidone, respectively. Average weight gain was significantly higher for the olanzapine group (mean = 4.6 kg, SD = 1.9) than for the risperidone (mean = 2.8 kg, SD = 1.3) and clozapine (mean = 2.5 kg, SD = 2.9) groups. Olanzapine and risperidone, but not clozapine, caused a disproportionately higher weight gain in children and adolescents in comparison to adults.

Family-based association study of serotonergic candidate genes and attention-deficit/hyperactivity disorder in a German sample

Alterations in the serotonergic pathway have been implicated in the pathogenesis of attention-deficit/hyperactivity disorder (ADHD). The aim of this study was to investigate seven genetic variants in three genes (serotonin transporter (5-HTT), serotonin receptor 1B (5-HTR1B) and serotonin receptor 2A (5-HTR2A)), which have previously been shown to be associated with ADHD. The polymorphisms under investigation were the 5-HTTLPR, the VNTR in intron 2 and the 3'UTR SNP in 5-HTT, the 5-HTR1B variations 861G>C and 102T>C, and the 5-HTR2A variations His452Tyr and 1438G>A. We genotyped these variants in a sample of 102 families with 229 children with ADHD according to DSM-IV criteria. Among the affected children, 69% fulfilled criteria for the combined type, 27% for the predominantly inattentive type, and 4% for the predominantly hyperactive-impulsive type. Associations were tested by the pedigree transmission disequilibrium test (PDT). All investigated polymorphisms in serotonergic candidate genes showed no association to ADHD in our sample. Earlier studies of these polymorphisms had also shown inconsistent results, with some studies reporting significant associations and others demonstrating no association. This discordance between studies may reflect variation in patient ascertainment criteria, genetic heterogeneity, too low statistical power for the expected effects or false positive results in the initial reports. We cannot rule out the possibility that other variations in the investigated genes contribute to the etiology of ADHD.

Very mild cases of Rett syndrome with skewed X inactivation

BACKGROUND

Rett syndrome, a common cause of mental retardation in females, is caused by mutations in the MECP2 gene. Most females with MECP2 mutations fulfil the established clinical criteria for Rett syndrome, but single cases of asymptomatic carriers have been described. It is therefore likely that there are individuals falling between these two extreme phenotypes.

OBJECTIVE

To describe three patients showing only minor symptoms of Rett syndrome.

FINDINGS

The patient with the best intellectual ability had predominantly psychiatric problems with episodes of uncontrolled aggression that have not been described previously in individuals with MECP2 mutations. All three patients had normal hand function, communicated well, and showed short spells of hyperventilation only under stress. Diagnosis in such individuals requires the identification of subtle signs of Rett syndrome in girls with a mild mental handicap. Analysis of the MECP2 gene revealed mutations that are often found in classical Rett syndrome. Skewed X inactivation was present in all three cases, which may explain the mild phenotype.

CONCLUSIONS

Because of skewed X inactivation, the phenotype of Rett patients may be very mild and hardly recognisable.

[Dysmorphophobia]

In the ICD-10 classification, the body dysmorphophobic (dysmorphic) disorder is subsumed under the code for somatoform or hypochondriacal disorders (F45.2). To the fore is an excessive preoccupation with an imagined, but not objectifiable, bodily defect, usually affecting a part of the body that is either exposed or considered to be of importance for the patient's attractiveness. In many cases, the patient insistently demands surgical correction. During the further course of the condition, depression, social phobia, obsessive-compulsive and self-destructive behavior may develop. The condition usually begins early in the patient's life, and the lifetime prevalence is estimated to be 5%. Since an involvement of the serotonergic system is assumed, selective serotonin reuptake inhibitors are considered to be the medication of first choice. Surgical interventions do not lead to remission but simply to a transference of symptoms. Referral to a psychiatric specialist with the aim of clarifying the diagnosis is indicated.

Microarray analysis reveals distinct gene expression patterns in the mouse cortex following chronic neuroleptic and stimulant treatment: implications for body weight changes

Atypical neuroleptics are associated with clinical significant weight gain, whereas stimulants are used as anorexiant drugs. The aim of this study was to examine gene expression changes in the mouse frontal cortex following chronic oral treatment with antipsychotics and a stimulant by microarray assessments. Twenty 10-12-week-old male C57BL6 mice received daily for 31 days either the typical neuroleptic haloperidol (1 mg/kg), the atypical neuroleptic clozapine (10 mg/kg) or the stimulant phenylpropanolamine (3 mg/kg). We identified a set of genes that was differently expressed between the neuroleptic-treated groups and the stimulant-treated group. Importantly, we found in the majority of gene alterations down-regulation in genes involved in ATP biosynthesis and lipid metabolism following the stimulant treatment, suggesting these genes as candidates that may regulate body weight. We also identified remarkable expression patterns of genes that encode signalling molecules (e.g. insulin, mitochondrial uncoupling protein 1) that are implicated in the control of food intake and are differently expressed in the neuroleptic groups.

A genome-wide scan for attention-deficit/hyperactivity disorder in 155 German sib-pairs

Three groups have previously performed genome scans in attention-deficit/hyperactivity disorder (ADHD); linkage to chromosome 5p13 was detected in all of the respective studies. In the current study, we performed a whole-genome scan with 102 German families with two or more offspring who currently fulfilled the diagnostic criteria for ADHD. Including subsequent fine mapping on chromosome 5p, a total of 523 markers were genotyped. The highest nonparametric multipoint LOD score of 2.59 (empirical genome-wide significance 0.1) was obtained for chromosome 5p at 17 cM (according to the Marshfield map). Subsequent analyses revealed (a) a higher LOD score of 3.37 at 39 cM for a quantitative severity score based on symptoms of inattention than for hyperactivity/impulsivity (LOD score of 1.11 at 59 cM), and (b) an HLOD of 4.75 (empirical genome-wide significance 0.001) based on a parametric model assuming dominant inheritance. The locus of the solute carrier 6A3 (SLC6A3; dopamine transporter 1; DAT1) localizes to 5p15.33; the gene has repeatedly been implicated in the etiology of ADHD. However, in our sample the DAT1 VNTR did not show association with ADHD. We additionally identified nominal evidence for linkage to chromosomes 6q, 7p, 9q, 11 q, 12q and 17p, which had also been identified in previous scans. Despite differences in ethnicity, ascertainment and phenotyping schemes, linkage results in ADHD appear remarkably consistent.

Transmission disequilibrium of polymorphic variants in the tryptophan hydroxylase-2 gene in attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is the most common behavioral disorder in childhood with substantial heritability. Pharmacological and molecular genetic studies as well as characterization of animal models have implicated serotonergic dysfunction in the pathophysiology of ADHD. Here, we investigated the effect of polymorphic variants in the gene of the tryptophan hydroxylase-2 (TPH2), the rate-limiting enzyme of serotonin (5-HT) synthesis in the brain, in children and adolescents with ADHD. We analyzed three single nucleotide polymorphisms (SNPs) in and downstream of the transcriptional control region of the TPH2 gene in 103 families with 225 affected children. Allelic association in families with more than one affected child was assessed using the pedigree disequilibrium test. Preferential transmissions were detected for the two SNPs in TPH2's regulatory region (rs4570625, P=0.049; rs11178997, P=0.034), but not for the third SNP in intron 2 (rs4565946, P=0.3517). Haplotype analysis revealed a strong trend of association between the regulatory region SNPs (rs4570625, rs11178997) and ADHD (P=0.064). Our results link potentially functional TPH2 variations to the pathophysiology of ADHD, and further support the relevance of 5-HT in disorders related to altered motor activity and cognitive processes.

Linkage analyses of chromosomal region 18p11-q12 in dyslexia

Dyslexia is characterized as a significant impairment in reading and spelling ability that cannot be explained by low intelligence, low school attendance or deficits in sensory acuity. It is known to be a hereditary disorder that affects about 5% of school aged children, making it the most common of childhood learning disorders. Several susceptibility loci have been reported on chromosomes 1, 2, 3, 6, 15, and 18. The locus on chromosome 18 has been described as having the strongest influence on single word reading, phoneme awareness, and orthographic coding in the largest genome wide linkage study published to date (Fisher et al., 2002). Here we present data from 82 German families in order to investigate linkage of various dyslexia-related traits to the previously described region on chromosome 18p11-q12. Using two- and multipoint analyses, we did not find support for linkage of spelling, single word reading, phoneme awareness, orthographic coding and rapid naming to any of the 14 genotyped STR markers. Possible explanations for our non-replication include differences in study design, limited power of our study and overestimation of the effect of the chromosome 18 locus in the original study.

Mutation screen of the brain derived neurotrophic factor gene (BDNF): identification of several genetic variants and association studies in patients with obesity, eating disorders, and attention-deficit/hyperactivity disorder

Several lines of evidence indicate an involvement of brain derived neurotrophic factor (BDNF) in body weight regulation and activity: heterozygous Bdnf knockout mice (Bdnf(+/-)) are hyperphagic, obese, and hyperactive; furthermore, central infusion of BDNF leads to severe, dose-dependent appetite suppression and weight loss in rats. We searched for the role of BDNF variants in obesity, eating disorders, and attention-deficit/hyperactivity disorder (ADHD). A mutation screen (SSCP and DHPLC) of the translated region of BDNF in 183 extremely obese children and adolescents and 187 underweight students was performed. Additionally, we genotyped two common polymorphisms (rs6265: p.V66M; c.-46C > T) in 118 patients with anorexia nervosa, 80 patients with bulimia nervosa, 88 patients with ADHD, and 96 normal weight controls. Three rare variants (c.5C > T: p.T2I; c.273G > A; c.*137A > G) and the known polymorphism (p.V66M) were identified. A role of the I2 allele in the etiology of obesity cannot be excluded. We found no association between p.V66M or the additionally genotyped variant c.-46C > T and obesity, ADHD or eating disorders. This article contains supplementary material, which may be viewed at the American Journal of Medical Genetics website at http://www.interscience.wiley.com/jpages/0148-7299:1/suppmat/index.html.

Validation of a quality of life questionnaire measuring the subjective fear of falling in nursing home residents

A quality of life scale was developed to measure the subjective fear of falling in nursing home residents. We assessed the dimensions fear of falling, daily living and social life within a randomized controlled trial of hip protector use. The Nottingham Health Profile (NHP) was used for validation. Statistical analysis covered factor analysis, internal consistency of subscales, construct and discriminant validity. Factor analysis revealed three reliable components (Cronbach's Alpha): fear of falling (0.92), social restriction due to limited mobility (0.74) and restriction by clothes due to the hip protector (0.72). The subscales fear of falling and social restriction were significantly intercorrelated with all subscales of the NHP. The new tool is a reliable and valid measure of fear of falling in nursing home residents. However, generalizability and applicability are limited by the small proportion of subjects able to complete the tests.

Transmission disequilibrium studies in children and adolescents with obsessive-compulsive disorders pertaining to polymorphisms of genes of the serotonergic pathway

Pharmacological and challenge study data showed an involvement of the serotonergic system in the development of obsessive-compulsive disorder (OCD). We studied transmission disequilibrium of polymorphisms in three candidate genes of the serotonergic pathway in 64 trios comprising patients with early onset OCD and both of their parents. Polymorphisms of the following genes were studied: tryptophan hydroxylase 1 (rs1800532), serotonin transporter (polymorphism in the promoter region; 5-HTTLPR) and the serotonin 1 B receptor (rs6296). This is, to our knowledge, one of the first family based association studies pertaining to children and adolescents with OCD. We did not detect transmission disequilibrium of the investigated polymorphisms in OCD. Hence, these polymorphisms do not play a major role in the genetic predisposition to early onset OCD.

Visual information processing in dyslexic children

OBJECTIVE

Several studies presented evidence for magnocellular deficits in dyslexics both in behavioural as well as in electrophysiological data of local electrode sites. We investigated two well-known paradigms (motion-onset and random-dot-kinematogram) with regard to global electrophysiological parameters.

METHODS

Twenty-one-channel event-related potentials (ERPs) of 16 dyslectic and 15 control children were analyzed with reference-independent methods. For each paradigm quasi stable microstates were identified by means of a data-driven segmentation procedure and compared between both groups.

RESULTS

Differences in global ERP responses between dyslexic and control children could be found for rapid moving gratings but not for the dot coherence.

CONCLUSIONS

Dyslexic children seem to have some highly specific visual deficits in processing moving stimuli. These deficits can be related to the magnocellular system.

Lebensqualität bei psychisch kranken Kindern und Jugendlichen

Zusammenfassung: Fragestellung: Das neu entwickelte krankheitsunspezifische Instrument zur Messung der Lebensqualität von Kindern und Jugendlichen (ILK, Mattejat et al., 1998 ) sollte hinsichtlich seiner Differenzierungsfähigkeit zwischen ambulanten und stationären psychiatrischen Stichproben überprüft werden. Methodik: 626 kinder- und jugendpsychiatrische Patienten aus regional unterschiedlichen Kliniken und Praxen wurde der ILK-Bogen vorgelegt. Die so gewonnenen Daten werden deskriptiv dargestellt und mit Hilfe logistischer Regressionen genauer analysiert. Ergebnisse: Während eine rein deskriptive Betrachtung zeigt, dass stationär behandelte Kinder und Jugendliche durchweg alle Lebensbereiche als belastender erleben, relativiert sich dieses Ergebnis durch die Regressionsanalyse. Hier zeigt sich, dass die deskriptiv gefundenen Unterschiede zwischen stationären und ambulanten Patienten teilweise auf Alters- und/oder Geschlechtseffekte zurückzuführen sind; in einigen Lebensbereichen jedoch erweisen sich die Unterschiede zwischen der ambulanten und stationären Stichprobe unter Berücksichtigung von Alter und Geschlecht als Kovariaten als durchaus substantiell. Schlussfolgerungen: Das ILK ist als effizientes ökonomisches Verfahren in der Lage, Lebensqualität in Abhängigkeit von dem Schweregrad psychiatrischer Störungen zu erfassen; darüber hinaus ist es sensitiv für Alters- und Geschlechtseffekte. Indem das ILK Bereiche mit verminderter Lebensqualität schnell und sicher identifiziert, bietet es Ansatzpunkte für Indikationsstellung, Therapieplanung und erste therapeutische Interventionen.

[Pharmacotherapy of compulsive disorders in childhood and adolescence]

OBJECTIVES

The review addresses the issue of the extent to which pharmacological treatment of obsessive-compulsive disorders (OCD) in childhood and adolescence is based on empirical studies.

METHODS

Current literature is evaluated, including studies of adult cohorts if these contain approaches relevant for the pharmacological treatment of children and adolescents.

RESULTS

The number of qualified empirical studies is few. These studies have shown clomipramine and serotonin-reuptake inhibitors to be very effective in the therapy of obsessive-compulsive disorders in childhood and adolescence. On the basis of the studies available, no specific recommendation can be made with regard to pharmacological dosage. For clomipramine the effective daily dose probably ranges somewhere between 75-150 mg, for fluoxetin between 20-60 mg, and for fluvoxamine between 100-250 mg. However, it must be kept in mind that in individual cases, improvement sometimes will not be noticeable until after 8 to 10 weeks of treatment have elapsed.

CONCLUSION

Clomipramine and serotonin-reuptake inhibitors are effective in the treatment of obsessive-compulsive disorders in children and adolescents. There is an urgent need for therapy studies of obsessive-compulsive disorders in childhood and adolescence. Placebo-controlled studies of pharmacological treatment, controlled studies of psychotherapeutic treatment, and comparative studies of pharmacological and psychotherapeutic approaches are necessary.

5-HT2A promoter polymorphism -1438G/A in children and adolescents with obsessive-compulsive disorders

Positive association between obsessive compulsive disorder (OCD) and the A-allele of the 5-HT(2A)-receptor promoter polymorphism -1438G/A has recently been reported in adults. We performed an association analysis of this polymorphism in 55 children and adolescents with OCD and in 223 controls consisting of unrelated students. We detected statistically significant differences in genotype (P < 0.05) and allele frequencies (P < 0.05) between individuals with OCD and controls. In this, to our knowledge, first association study based on children and adolescents with OCD, we confirm an association of the A-allele of the 5-HT2A receptor gene with OCD.

[Formal genetic findings in attention-deficit/hyperactivity-disorder]

Twin, family and adoption studies have led to a solid understanding of the contribution of both genetic and environmental factors to the development of attention deficit/hyperactivity disorder (ADHD). We review recent studies under consideration of both methodological aspects and relevant findings. Heritability estimates in the range of 0.6 - 0.8 surpass those for most other child and adolescent psychiatric disorders. First degree relatives have elevated rates for ADHD, affective disorders, conduct disorders and substance abuse and dependency. The ADHD subtype of the index patient does not predict the subtype of other family members affected with ADHD; hence non-genetic factors seemingly account for this intrafamilial variability. Because the familial rates for ADHD are not higher in families of female in comparison to male index patients, there is no indication that the genetic loading is higher in affected females. Recently, rater effects have been discussed broadly: Whereas the heritability estimates are uniformly high independent of the informant (mother, father, teacher), the correlations between quantitatively rated symptoms are low between different informants. Knowledge of the formal genetic aspects of ADHD is a prerequisite for understanding the results of recent molecular genetic studies.

Electrophysiological investigation of the effectiveness of methylphenidate in children with and without ADHD

The Continuous Performance Test (CPT) is an appropriate instrument for assessment of correlates at the brain electrical activity level of attention and response to stimulant medication. The aim of the study was to confirm at the electrophysiological level the clinical effectiveness of methylphenidate (MPH) in children with attention deficit / hyperactivity disorder (ADHD); to this end, a comparative study of hyperactive and healthy control children was undertaken, employing a modified CPT test. Twenty-one channel ERPs from 17 hyperactive boys, with and without MPH treatment, and from 20 healthy control children were analyzed with reference-independent techniques. The resulting quasi-stabile microstates correspond to the time ranges of the conventional ERP components P100, P200 and P300 (with the subcomponents P3a and P3b) and could be discriminated by means of data-based segmentation. The P3a amplitudes of the hyperactive children, in each case with and without MPH medication, were compared with those of healthy controls. P3a segment amplitudes were significantly lower in non-medicated ADHD patients than in healthy children, both following positive and inhibitory stimulus conditions. A significant medication effect was detected following MPH treatment: segment 3 amplitudes in MPH-treated hyperactive children were not significantly different from those of healthy controls. MPH exerts a highly potent effect on stimulus recognition and resulting consequences. Application of the CPT-OX enables the reliable measurement of electrophysiological correlates of the clinical effectiveness of MPH under different stimulus conditions.

[Day care treatment of 2 siblings with elective mutism]

OBJECTIVES

This case report deals with the day care treatment of two seven- and eight-year-old siblings with elective mutism. Their treatment entails a combination of psychopharmacological and intensive behavior therapy. The multimodal therapeutic process is presented together with continuing psychosocial steps. Behavioral intervention focuses on building verbal expressive capacity, reducing speech anxiety in social situations and generalization to non-therapeutic situations. The case report is discussed in the context of the current literature on elective mutism.

[Children in the drive for thinness. How early anorexia nervosa modifies development]

In adolescents and young women, the prevalence of anorexia nervosa is 0.5-1%. Approximately 5% of all anorectics are younger than 12 years of age. Frequent psychiatric concomitant conditions that develop during the long-term course are depression or dysthymia (in our own patient material approximately 14%) and anxiety (some 28%). In our own studies, healing success was achieved in 54% of the cases; 18% achieved partial remission with remnant symptoms of an unspecific eating disorder, and 28% continued to exhibit anorectic and/or bulimic symptoms. Of prognostic importance were eating disorders in the child's first year and the duration of the catamnesis. The prognosis of anorexia nervosa with onset in childhood does not appear to differ significantly from that of anorexia with onset in adolescence or adulthood.

A study of cranial computer tomograms in very early and early onset schizophrenia

The cranial computer-assisted tomograms of 19 patients suffering from schizophrenic psychoses with onset by age of 14 were examined. The emphasis was on the extent of the inner liquor spaces. Compared to healthy controls, at the beginning of illness a significant enlargement was revealed only in the patient group with very early onset schizophrenia (VEOS, onset prior to the age of 12), whereas children with early onset (EOS, 12 to 14 years of age) showed no significant brain pathology. As a second result, an increase in the extent of the inner liquor spaces seems to correlate with the duration of illness. It is therefore concluded that psychoses interfere with neurodevelopmental processes and cause more severe brain pathology in very young children, already detectable at the onset of the illness. EOS, on the other hand, induces progressive morphological abnormalities over the course of the illness.