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GH secretagogue receptor (GHSR, ghrelin receptor) is involved in regulation of body weight and GH secretion. We initially analyzed two single-nucleotide polymorphisms of the GHSR in up to 184 extremely obese children and adolescents and up to 184 healthy underweight students. The frequency of the 171T allele of rs495225 was higher in our obese samples (75.0%) than in the underweight individuals (70.2%; nominal P = 0.14). This trend could not be substantiated in an additional association study in 270 obese and 145 underweight and normal weight individuals and in a transmission disequilibrium test based on 387 obesity trios (transmission rate of 171T, 51.8%; nominal P = 0.53). Additionally, the coding region of GHSR was systematically screened, and seven sequence variants were identified in 93 obese, 96 normal weight, and 94 underweight individuals and 43 children with short normal stature (SNS). Five silent single-nucleotide polymorphisms showed similar genotype frequencies in the different weight groups and SNS children (all nominal P > 0.3). Two novel missense variants were detected only in one obese carrier and one SNS child, respectively. In conclusion, we did not obtain conclusive evidence for an involvement of the ghrelin receptor gene in body weight regulation or SNS in our study groups.

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.

We propose and study a new method to nonparametrically estimate a discontinuity of a regression function. The optimal rate of convergence n - 1 is obtained under minimal assumptions. No smoothing is required.

Objective Osteopontin (OPN) is an extracellular matrix protein that plays an integral role in myocardial remodelling and has previously been shown to be a valuable biomarker in cardiovascular disease. Because of the concentric myocardial hypertrophy associated with severe, symptomatic aortic stenosis (AS), we hypothesised that OPN expression may have a prognostic value in patients undergoing transcatheter aortic valve implantation (TAVI). Methods We prospectively included 217 patients undergoing TAVI between February 2011 and December 2013 with a median follow-up of 349 days. Twenty healthy individuals from the same age range free from structural heart disease served as controls. The primary endpoint for the analysis was survival time. Results Median preprocedural OPN levels (675 ng/mL; IQR 488.5–990.5 ng/mL) were significantly higher in patients with severe aortic valve stenosis compared with healthy controls (386 ng/mL; IQR 324.5–458, p

In-patient treatment (IP) is the treatment setting of choice for moderately-to-severely ill adolescents with anorexia nervosa, but it is costly, and the risks of relapse and readmissions are high. Day patient treatment (DP) is less expensive and might avoid problems of relapse and readmission by easing the transition from hospital to home. We investigated the safety and efficacy of DP after short inpatient care compared with continued IP.For this multicentre, randomised, open-label, non-inferiority trial, we enrolled female patients (aged 11-18 years) with anorexia nervosa from six centres in Germany. Patients were eligible if they had a body-mass index (BMI) below the tenth percentile and it was their first admission to hospital for anorexia nervosa. We used a computer-generated randomisation sequence to randomly assign patients to continued IP or DP after 3 weeks of inpatient care (1:1; stratified for age and BMI at admission). The treatment programme and treatment intensity in both study groups were identical. The primary outcome was the increase in BMI between the time of admission and a 12-month follow-up adjusted for age and duration of illness (non-inferiority margin of 0·75 kg/m(2)). Analysis was done by modified intention to treat. This trial is registered with the International Standard Randomised Controlled Trial Number Register, number ISRCTN67783402, and the Deutsches Register Klinischer Studien, number DRKS00000101.Between Feb 2, 2007, to April 27, 2010, we screened 660 patients for eligibility, 172 of whom we randomly allocated to treatment: 85 to IP and 87 to DP. DP was non-inferior to IP with respect to the primary outcome, BMI at the 12-month follow-up (mean difference 0·46 kg/m(2) in favour of DP (95% CI, -0·11 to 1·02; pnon-inferiority0·0001). The number of treatment-related serious adverse events was similar in both study groups (eight in the IP group, seven in the DP group). Three serious adverse events in the IP group and two in the DP group were related to suicidal ideation; one patient in the DP attempted suicide 3 months after she was discharged.DP after short inpatient care in adolescent patients with non-chronic anorexia nervosa seems no less effective than IP for weight restoration and maintenance during the first year after admission. Thus, DP might be a safe and less costly alternative to IP. Our results justify the broad implementation of this approach.German Ministry for Education and Research.

Several genome-wide screens for asthma and related phenotypes have been published to date but data on fine-mapping are scarce. For higher resolution we performed a fine-mapping study with 2 cM average spacing in often discussed asthma candidate regions (2p, 5q, 6p, 7p, 9q, 11p, and 12q) to narrow down the regions of interest. All participants of a Caucasian family study (97 families with at least two affected sib pairs) were genotyped for 49 supplementary polymorphic dinucleotide markers. Our results indicate increased evidence for linkage on chromosome 6p, 9q, and 12q. These candidate regions were further analyzed with SNP polymorphisms in the endothelin 1 (EDN1), lymphotoxin alpha (LTA), and neuronal nitric oxide synthase (NOS1) genes. In addition, IL4 -590C>T and IL10 -592C>A, localized on chromosomes 5q and 1q, respectively, have been analyzed for SNP association. Of the six SNPs tested, four revealed weak association with the examined phenotypes. These are the IL10 -592C>A SNP in the interleukin 10 gene (p=0.036 for eosinophil cell counts), the 4124T>C SNP in EDN1 (p=0.044 for asthma), the 3391C>T SNP in NOS1 with eosinophil cell counts (p=0.0086), and the 5266C>T polymorphism, also in the NOS1 gene, for high IgE levels (p=0.022). In summary, fine mapping data enable us to confine asthma candidate regions, while variants of EDN1 and NOS1, or nearby genes, may play an important role in this context. Hum Mutat 18:327–336, 2001. © 2001 Wiley-Liss, Inc.

Objective To investigate the olfactory/gustatory functions of patients with inflammatory bowel disease (IBD) by smell/taste tests, and to determine if disease activity or medication might influence the olfactory/gustatory functions of patients. Patients and methods In total, 59 IBD patients (37 Crohn's disease (CD) and 22 ulcerative colitis (UC) patients) were studied using "Sniffin' sticks" and "taste strips" for olfactory and gustatory tests, respectively, and compared to healthy controls and published normative data. Results Among IBD (CD and UC) patients, the values for odor threshold, but not for odor identification or discrimination, were significantly lower than that of the normative data. Further, these patients showed lower values than the normative taste values and the control group for all tastes, except sour; 57.6% of the IBD patients were hyposmic, while 30.5% were hypogeusic. Subjective self-assessments showed that the patients were not aware of their reduced olfactory/gustatory functions. There were no relevant differences in taste and smell abilities between the CD and UC patients. Disease activity and treatment did not influence the olfactory/gustatory functions. Conclusion IBD (CD and UC) patients exhibited significant reductions in the olfactory and gustatory functions. Therefore, patients should be tested by smell/taste tests, in order to be adequately informed of their olfactory/gustatory functions and provided an understanding of how to overcome their limitations, and thus improve their quality of life.

Due to their sub-normally low fat mass, leptin levels in patients with acute anorexia nervosa (AN) are well below reference levels for age and sex-matched controls. This hypoleptinemia entails endocrinological and behavioral characteristics observed in AN patients during starvation. We aimed to study the appropriateness of hypoleptinemia as a diagnostic marker for AN by assessing sensitivity, specificity and likelihood ratios for different referral serum leptin levels for predicting anorexia nervosa and healthy leanness. For prediction, we additionally generated a score based on a multivariate logistic model including body mass index (BMI; kg/m²) and leptin level. For this purpose, we measured leptin levels in 74 female patients with acute AN upon admission for inpatient or outpatient treatment. Adolescent and adult patients were recruited according to DSM-IV criteria from two multi-center studies. Additionally, leptin levels were measured in 65 female healthy, lean students. Mean serum leptin level was significantly decreased in patients with AN compared to underweight controls (0.87 ± 0.90 vs. 6.43 ± 3.55 μg/L, p

While an interactive effect of genes with adverse life events is increasingly appreciated in current concepts of depression etiology, no data are presently available on interactions between genetic and environmental (G × E) factors with respect to personality and related disorders. The present study therefore aimed to detect main effects as well as interactions of serotonergic candidate genes (coding for the serotonin transporter, 5-HTT; the serotonin autoreceptor, HTR1A; and the enzyme which synthesizes serotonin in the brain, TPH2) with the burden of life events (#LE) in two independent samples consisting of 183 patients suffering from personality disorders and 123 patients suffering from adult attention deficit/hyperactivity disorder (aADHD). Simple analyses ignoring possible G × E interactions revealed no evidence for associations of either #LE or of the considered polymorphisms in 5-HTT and TPH2. Only the G allele of HTR1A rs6295 seemed to increase the risk of emotional-dramatic cluster B personality disorders (p = 0.019, in the personality disorder sample) and to decrease the risk of anxious-fearful cluster C personality disorders (p = 0.016, in the aADHD sample). We extended the initial simple model by taking a G × E interaction term into account, since this approach may better fit the data indicating that the effect of a gene is modified by stressful life events or, vice versa, that stressful life events only have an effect in the presence of a susceptibility genotype. By doing so, we observed nominal evidence for G × E effects as well as main effects of 5-HTT-LPR and the TPH2 SNP rs4570625 on the occurrence of personality disorders. Further replication studies, however, are necessary to validate the apparent complexity of G × E interactions in disorders of human personality.

Attention deficit/hyperactivity disorder (ADHD) is a highly heritable neurodevelopmental disorder of childhood onset. Clinical and biological evidence points to shared common central nervous system (CNS) pathology of ADHD and restless legs syndrome (RLS). It was hypothesized that variants previously found to be associated with RLS in two large genome-wide association studies (GWA), will also be associated with ADHD. SNPs located in MEIS1 (rs2300478), BTBD9 (rs9296249, rs3923809, rs6923737), and MAP2K5 (rs12593813, rs4489954) as well as three SNPs tagging the identified haplotype in MEIS1 (rs6710341, rs12469063, rs4544423) were genotyped in a well characterized German sample of 224 families comprising one or more affected sibs (386 children) and both parents. We found no evidence for preferential transmission of the hypothesized variants to ADHD. Subsequent analyses elicited nominal significant association with haplotypes consisting of the three SNPs in BTBD9 (chi2 = 14.8, df = 7, nominal p = 0.039). According to exploratory post hoc analyses, the major contribution to this finding came from the A-A-A-haplotype with a haplotype-wise nominal p-value of 0.009. However, this result did not withstand correction for multiple testing. In view of our results, RLS risk alleles may have a lower effect on ADHD than on RLS or may not be involved in ADHD. The negative findings may additionally result from genetic heterogeneity of ADHD, i.e. risk alleles for RLS may only be relevant for certain subtypes of ADHD. Genes relevant to RLS remain interesting candidates for ADHD; particularly BTBD9 needs further study, as it has been related to iron storage, a potential pathophysiological link between RLS and certain subtypes of ADHD.

Genetic and environmental risk factors and their interactions contribute to the development of complex diseases. In this review, we discuss methodological issues involved in investigating gene-environment (G x E) interactions in genetic-epidemiological studies of complex diseases and their potential relevance for clinical application. Although there are some important examples of interactions and applications, the widespread use of the knowledge about G x E interaction for targeted intervention or personalized treatment (pharmacogenetics) is still beyond current means. This is due to the fact that convincing evidence and high predictive or discriminative power are necessary conditions for usefulness in clinical practice. We attempt to clarify conceptual differences of the term 'interaction' in the statistical and biological sciences, since precise definitions are important for the interpretation of results. We argue that the investigation of G x E interactions is more rewarding for the detailed characterization of identified disease genes (ie at advanced stages of genetic research) and the stratified analysis of environmental effects by genotype or vice versa. Advantages and disadvantages of different epidemiological study designs are given and sample size requirements are exemplified. These issues as well as a critical appraisal of common methodological concerns are finally discussed.

Accounting for interactions with environmental factors in association studies may improve the power to detect genetic effects and may help identifying important environmental effect modifiers. The power of unphased genotype-versus haplotype-based methods in regions with high linkage disequilibrium (LD), as measured by D', for analyzing gene × environment (gene × sex) interactions was compared using the Genetic Analysis Workshop 15 (GAW15) simulated data on rheumatoid arthritis with prior knowledge of the answers. Stepwise and regular conditional logistic regression (CLR) was performed using a matched case-control sample for a HLA region interacting with sex. Haplotype-based analyses were performed using a haplotype-sharing-based Mantel statistic and a test for haplotype-trait association in a general linear model framework. A step-down minP algorithm was applied to derive adjusted p-values and to allow for power comparisons. These methods were also applied to the GAW15 real data set for PTPN22. For markers in strong LD, stepwise CLR performed poorly because of the correlation/collinearity between the predictors in the model. The power was high for detecting genetic main effects using simple CLR models and haplotype-based methods and for detecting joint effects using CLR and Mantel statistics. Only the haplotype-trait association test had high power to detect the gene × sex interaction. In the PTPN22 region with markers characterized by strong LD, all methods indicated a significant genotype × sex interaction in a sample of about 1000 subjects. The previously reported R620W single-nucleotide polymorphism was identified using logistic regression, but the haplotype-based methods did not provide any precise location information.

Previous genome-wide linkage studies applied the affected sib-pair design; one investigated extended pedigrees of a genetic isolate. Here, results of a genome-wide high-density linkage scan of attention-deficit/hyperactivity disorder (ADHD) using an array-based genotyping of approximately 50 K single nucleotide polymorphism (SNPs) markers are presented. We investigated eight extended pedigrees of German origin that were non-related, not part of a genetic isolate and ascertained on the basis of clinical referral. Two parametric analyses maximizing LOD scores (MOD) and a non-parametric analysis for both a broad and a narrow phenotype approach were conducted. Novel linkage loci across all families were detected at 2q35, 5q13.1, 6q22-23 and 14q12, within individual families at 18q11.2-12.3. Further linkage regions at 7q21.11, 9q22 and 16q24.1 in all families, and at 1q25.1, 1q25.3, 9q31.1-33.1, 9q33, 12p13.33, 15q11.2-13.3 and 16p12.3-12.2 in individual families replicate previous findings. High-resolution linkage mapping points to several novel candidate genes characterized by dense expression in the brain and potential impact on disorder-relevant synaptic transmission. Our study provides further evidence for common gene effects throughout different populations despite the complex multifactorial etiology of ADHD.

Copy number variants (CNVs) are pieces of genomic DNA of 1000 base pairs or longer which occur in a given genome at a different frequency than in a reference genome. Their importance as a source for phenotypic variability has been recognized only in the last couple of years. Chromosomal deletions can be seen as a special case of CNVs where stretches of DNA are missing in certain lines when compared to the reference genome of the mouse line C57BL/6, for example. Based upon more than 8 million single nucleotide polymorphisms (SNPs) in the fifteen inbred mouse lines which were determined in a whole genome chip based resequencing project by Perlegen Sciences, we detected 20 166 such long chromosomal deletions. They cover altogether between 4.4 million and 8.8 million base pairs, depending on the mouse line. Thus, their extent is comparable to that of SNPs. The chromosomal deletions were found by searching for clusters of missing values in the genotyping data by applying bioinformatics and biostatistical methods. In contrast to isolated missing values, clusters are likely the consequence of missing DNA probe rather than of a failed hybridization or deficient oligos. We analyzed these deletion sites in various ways. Twenty-two percent of these deletion sites overlap with exons; they could therefore affect a gene’s functioning. The corresponding genes seem to exist in alternative forms, a phenomenon that reminds of the alternative forms of mRNA generated during gene splicing. We furthermore detected statistically significant association between hundreds of deletion sites and fat weight at the age of eight weeks.

Altered neurotransmission has been suggested to be a crucial factor in the pathophysiology of attention-deficit/hyperactivity disorder ADHD. Subsequently genes encoding for synaptic proteins have been investigated in candidate gene studies. These proteins mediate the release of neurotransmitters into the synaptic cleft in the process of signal transduction by forming a transient complex, enabling the junction of vesicle and synaptic membrane. One of the core proteins of this complex is the synaptosomal-associated protein 25 (SNAP25). It is one of the most validated candidate genes in ADHD according to meta-analyses. However, differing results were observed in previous studies, some of which were not able to observe association with ADHD. In this study we aimed to investigate association of genetic variants of SNAP25 located in the putative promoter region of SNAP25 and a SNP in intron 8, previously reported to associated with ADHD. A family based design was applied to detect preferential transmission of genetic variants. In our German ADHD sample no preferential transmission of either variant could be observed. Further investigation considering sub-sample analysis regarding response to D-amphetamine could enlight the role of SNAP25 in ADHD.

Previously, we had reported a genome-wide scan for attention-deficit/hyperactivity disorder (ADHD) in 102 families with affected sibs of German ancestry; the highest multipoint LOD score of 4.75 was obtained on chromosome 5p13 (parametric HLOD analysis under a dominant model) near the dopamine transporter gene (DAT1). We genotyped 30 single nucleotide polymorphisms (SNPs) in this candidate gene and its 5' region in 329 families (including the 102 initial families) with 523 affected offspring. We found that (1) SNP rs463379 was significantly associated with ADHD upon correction for multiple testing (P=0.0046); (2) the global P-value for association of haplotypes was significant for block two upon correction for all (n=3) tested blocks (P=0.0048); (3) within block two we detected a nominal P=0.000034 for one specific marker combination. This CGC haplotype showed relative risks of 1.95 and 2.43 for heterozygous and homozygous carriers, respectively; and (4) finally, our linkage data and the genotype-IBD sharing test (GIST) suggest that genetic variation at the DAT1 locus explains our linkage peak and that rs463379 (P

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.

Attention-Deficit and Hyperactivity Disorder (ADHD) is a common child and adolescent psychiatric disorder with a prevalence rate of 3-7%. Formal genetic studies provided an estimated heritability of 0.6-0.8 and an approximately five-fold elevated risk for ADHD in first-degree relatives. Currently, four genome scans have led to the identification of chromosomal regions potentially relevant in ADHD; especially the evidence for linkage to chromosome 5p13 is convincing. Meta-analyses of a large number of candidate gene studies suggest association with gene variants of the dopaminergic receptors DRD4 and DRD5, the serotonergic receptor HTR1B, and the synaptosomal receptor protein (SNAP-25). Hyperactivity has been investigated particularly in animal models, focusing on knockout- and quantitative trait loci (QTL) designs, with promising results for the dopaminergic system. It is likely that several gene polymorphisms with moderate to small effect sizes contribute to the phenotype ADHD; different combinations of such predisposing variants presumably underlie ADHD in different individuals. Therefore, large samples for molecular genetic studies are mandatory to detect these polymorphisms. Accordingly, several of today's findings have to be regarded as preliminary. The understanding of ADHD's neurobiology may be advanced by new technologies, such as SNP-based genome scans performed with gene chips comprising 10,000-1,000,000 SNPs, as well as using more sophisticated animal model designs.

The prevalence and consequences of co-morbid axis-I and axis-II disorders as well as personality traits were examined in a large cohort of adult attention-deficit/hyperactivity disorder (AADHD) at a tertiary referral center.In- and outpatients referred for diagnostic assessment of AADHD were screened. 372 affected probands were examined by means of the Structured Clinical Interview of DSM-IV axis-I/II disorders, the Revised NEO Personality Inventory (NEO-PI-R), and the Tridimensional Personality Questionnaire (TPQ).Lifetime co-morbidity with mood disorders was 57.3%, with anxiety disorders 27.2%, and with substance use disorders 45.0%. The histrionic personality disorder (35.2%) was the most frequent personality disorder. AADHD patients exhibited significantly altered scores on most of the NEO-PI-R and TPQ personality dimensions. The extent of substance abuse and dependence, as well as the presence of antisocial personality disorder alone or the cumulative number of other specific personality disorders was associated with lower psychosocial status (p.0001).In a cohort of patients with AADHD referred to a single tertiary center co-morbidity with axis-I/II disorders was remarkably prevalent. In AADHD co-morbid mood, anxiety, and personality disorders as well as substance abuse/dependence is likely to be predictive of poor outcome.

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.

Stature is a highly heritable trait under both polygenic and major gene control. We aimed to identify genetic regions linked to idiopathic short stature (ISS) in childhood, through a whole genome scan in 92 families each with two affected children with ISS, including constitutional delay of growth and puberty and familial short stature. Linkage analysis was performed for ISS, height and bone age retardation. Chromosome 12q11 showed significant evidence of linkage to ISS and height (maximum non-parametric multipoint LOD scores 3.18 and 2.31 at 55-58 cM, between D12S1301 and D12S1048), especially in sister-sister pairs (LOD score of 1.9 for ISS in 22 pairs). These traits were also linked to chromosomes 1q12 and 2q36. The region on chromosome 12q11 had previously shown significant linkage to adult stature in several genome scans and harbors the vitamin D receptor gene, which has been associated with variation in height. A single nucleotide polymorphism (SNP) (rs10735810, FokI), which leads to a functionally relevant alteration at the protein level, showed preferential transmission of the transcriptionally more active G-allele to affected children (P=0.04) and seems to be responsible for the observed linkage (P=0.05, GIST test). Bone age retardation showed moderate linkage to chromosomes 19p11-q11 and 7p14 (LOD scores 1.69 at 57 cM and 1.42 at 50 cM), but there was no clear overlap with linkage regions for stature. In conclusion, we identified significant linkage, which might be due to a functional SNP in the vitamin D receptor (VDR) gene and could be responsible for up to 34% of ISS cases in the population.

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. © 2004 Wiley-Liss, Inc.

Objective. In children with idiopathic short stature (ISS), studies investigating body mass index (BMI) or parameters of satiety regulation are scarce, and studies analyzing eating behavior are lacking. Methods. We recruited 214 children (123 index cases and 91 siblings) with ISS from 123 families. Affected children had to have a body height Results. Compared with population norms, BMI was significantly lower (mean: −0.33 standard deviation score). Furthermore, there was decreased food responsiveness (mean Child Eating Behavior Questionnaire score: 1.9; population mean: 2.4), reduced enjoyment of food (3.2 vs 3.9), emotional undereating (2.6 vs 3.0), lower desire to drink (2.0 vs 2.8), and increased fussiness over food (3.2 vs 2.9). When the sample was subdivided into the 2 groups of “good” and “poor” eaters according to the mothers' assessment of the current eating behavior, reduction in BMI as well as the behavioral characteristics already delineated in the total sample were found to be even more consistent in the subgroup of poor eaters. In the total sample of our children, as well as in both subgroups, serum leptin (adjusted for gender, BMI, and Tanner stage) was found to be moderately raised but did not differ between poor and good eaters. Total serum ghrelin was not different between poor and good eaters. Conclusions. Our clinical, behavioral, and endocrinologic findings in patients with ISS point to an altered eating behavior that possibly contributes to their short stature.

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. © 2005 Nature Publishing Group All rights reserved.

The melanocortin-4 receptor gene ( MC4R ) is involved in central energy homeostasis and body weight regulation. Both endogenous anorexigenic and orexigenic ligands bind to the receptor.1 Under normal conditions, the anorexigenic tone prevails as revealed by the fact that Mc4r knock-out mice2 develop elevated body weight. Mc4r−/− mice show higher food intake but a similar metabolic rate and similar decreased physical activity compared to wild type (WT) mice of the same strain.2–4 In comparison to a standard low fat diet, this deviant regulation of energy homeostasis is even more pronounced upon intake of a moderately fat diet,5 which leads to an even higher body mass. In all studies, the effect on body weight is smaller in heterozygous than in homozygous knockout mice, but the exact degree of dominance is not clear. In heterozygous Mc4r+/− animals, body mass is increased on average by about 7–45% and in homozygous Mc4r−/− by 50–100% compared to WT2–5 with substantial overlap between groups. The mutations might have a sex dependent effect, but the results are contradictory. In one study, the effect in males was only about half of that in females.2 However, two studies did not detect a sex by genotype interaction in this Mc4r−/− strain.4,5 One study in a different knockout line of the same inbred strain found a sex by genotype interaction in the opposite direction, with only a marginal effect in heterozygous females whereas heterozygous males had a body weight intermediate between WT and homozygous knockouts.3 The first mutations in the human MC4R gene were reported in extremely obese probands.6–8 Since then, several other studies investigated the association of different MC4R mutations with obesity. According to a recent overview,9 at least 34 putatively functionally relevant …

Two genome wide scans, one of which was subsequently extended, have led to the identification of different chromosomal regions assumed to harbour genes underlying attention-deficit/hyperactivity disorder (ADHD). Some of these regions were also identified in patients with autism and/or dyslexia. The only region for which both studies detected a LOD score >1 was on chr 5p13 which is in the vicinity of the location of the candidate gene DAT1. The candidate gene approach has revealed the most robust and replicated findings for DRD4, DRD5, and DAT1 polymorphisms. Meanwhile interesting endophenotype studies have also been conducted suggesting a genetic basis for different diagnostic and therapeutic criteria. Animal studies for ADHD have investigated especially hyperactivity and have focused mainly on knockout and QTL designs. In knockout mice models the most promising results were obtained for genes of the dopaminergic pathway. QTL results in rodents suggest multiple loci underlying different forms of natural and induced hyperactivity. The molecular results mentioned above are presented and discussed in detail, thus providing both clinicians and geneticists with an overview of the current research status of this important child and adolescent psychiatric disorder.

Non-syndromic syndactylies have been classified into five major types (I-V), all showing autosomal dominant mode of inheritance. Later, the classification was extended and three additional variants (VI-VIII) were defined. Type VII, the Cenani-Lenz syndactyly, is the only non-syndromic, autosomal recessive type. It is characterized by fusion of all phalanges with metacarpal synostosis, dislocated and dysplastic carpals and infrequently, radio-ulnar fusion. Here, we present a Pakistani family with a novel non-syndromic autosomal recessive syndactyly manifesting a unique combination of clinical features. In both hands, reduction of certain phalanges is evident. Radiological examination shows synostosis of third and fourth metacarpals bearing single phalanges. The first three toes are webbed, with hypoplastic terminal phalanx in all the toes. Besides Cenani-Lenz syndactyly, the phenotype segregating in our family is the second well-documented autosomal recessive, non-syndromic syndactyly. A phenotype similar to our family was described in a Turkish kindred but was considered to be a homozygous expression of type I syndactyly. Since the clinical features in our family had minimal overlap with syndactyly types I, II, and III, we have performed microsatellite marker screening to look for the cosegregation of this phenotype with any of the known loci for these respective types. We show that the phenotype in our family is not linked to chromosomal regions 2q34-q36, 2q31, and 6q22-q23 encompassing loci for syndactyly types I, II, and III.

Recently, Branson and coworkers reported a strong association between binge-eating disorder (BED) and variants in the melanocortin-4 receptor gene (MC4R). In the current study, we compared the eating behavior of 43 obese probands with functionally relevant MC4R mutations and of 35 polymorphism carriers (V103I or I251L) with wild-type carriers. The module for eating disorders of the Composite International Diagnostic Interview was used to identify binge-eating behavior. The Three-Factor Eating Questionnaire and the Leeds Food Frequency Questionnaire were used to assess restrained eating, disinhibition, hunger and percent total energy intake as fat. No significant differences between carriers of MC4R variants and wild-type carriers were detected. In particular, we found no evidence for an increased rate of binge-eating behavior in obese carriers of MC4R variants. Our findings do not support the strong association between BED and MC4R carrier status.

Objectives: The use of conventional Transmission/Disequilibrium tests in the analysis of candidate-gene association studies requires the precise and complete pre-specification of the total number of trios to be sampled to obtain sufficient power at a certain significance level (type I error risk). In most of these studies, very little information about the genetic effect size will be available beforehand and thus it will be difficult to calculate a reasonable sample size. One would therefore wish to reassess the sample size during the course of a study. Method: We propose an adaptive group sequential procedure which allows for both early stopping of the study with rejection of the null hypothesis (H₀) and for recalculation of the sample size based on interim effect size estimates when H₀ cannot be rejected. The applicability of the method which was developed by Müller and Schäfer [Biometrics 2001;57:886–891] in a clinical context is demonstrated by a numerical example. Monte Carlo simulations are performed comparing the adaptive procedure with a fixed sample and a conventional group sequential design. Results: The main advantage of the adaptive procedure is its flexibility to allow for design changes in order to achieve a stabilized power characteristic while controlling the overall type I error and using the information already collected. Conclusions: Given these advantages, the procedure is a promising alternative to traditional designs.

Objectives: Confidence intervals for genotype relative risks, for allele frequencies and for the attributable risk in the case parent trio design for candidate-gene studiesare proposed which can be easily calculated from the observed familial genotype frequencies. Methods: Likelihood theory and the delta method were used to derive point estimates and confidence internals. We used Monte Carlo simulations to show the validity of the formulae for a variety of given modes of inheritance and allele frequencies and illustrated their usefulness by applying them to real data. Results: Generally these formulae were found to be valid for ‘sufficiently large’ sample sizes. For smaller sample sizes the estimators for genotype relative risks tended to be conservative whereas the estimator for attributable risk was found to be anti-conservative for moderate to high allele frequencies. Conclusions: Since the proposed formulae provide quantitative information on the individual and epidemiological relevance of a genetic variant they might be a useful addition to the traditional statistical significance level of TDT results.

To identify susceptibility gene regions for complex diseases a combined linkage analysis of several genome scans might give additional insights to individual studies. In this article we consider different weighting schemes to combine the score statistics of individual studies to an overall statistic within multipoint nonparametric linkage analysis by GENEHUNTER/ALLEGRO. With the Genetic Analysis Workshop (GAW) 12 asthma data sets the weights are dominated by the large differences in the relevant sample sizes.

BMC psychiatry 13, 308 (2013). doi:10.1186/1471-244X-13-308, Published by BioMed Central, London

Introduction. Transcranial direct current stimulation (tDCS) is a non-invasive method of modulating brain activity. Previous studies with common tDCS montages have shown that there are positive effects on the left inferior dorsolateral prefrontal cortex (lDLPFC) for both healthy and clinical population like improvement of the working memory. Nevertheless, there is still lack of clear guidelines and safety instructions, probably due to not specific enough simulation montages, especially when focusing on pediatric population. This study aims to investigate behavioral outcome of multichannel tDCS over the lDLPFC in healthy children and adolescents. Therefore, tDCS was coupled with a memory task, especially focusing on accuracy and reaction time changes. Methods. The study was approved by the Ethic Committee of the Faculty of Medicine of Kiel University. The study was conducted in a double-blinded, randomized, sham-controlled design. 28 healthy children and adolescents (Age range: 10–17 years, mean age = 14,18, SD = 2,23) were included in the analysis. In four separate sessions, they received multichannel 2 mA anodal or sham tDCS for 20 minutes over the left DLPFC before or during working memory task (2 back task). At the behavioral level response time and accuracy for N-back task were evaluated. Additionally, safety and tolerability of multichannel tDCS has been investigated by written questionnaires. For multichannel 2 mA tDCS over DLPFC we used a 6-channel solution (3.14 cm2 circular electrodes; AF3 (897 μΑ), AF7 (284 μΑ), F3 (819 μΑ), Fp2 (−1000 μΑ) und T7 (−1000 μΑ)). Before, during and after stimulation 32 channel EEG was recorded in order to demonstrate neurophysiological changes. All materials required for the stimulations and EEG recording were obtained from Neuroelectrics (Barcelona, Spain). Results. All participants tolerated the stimulation well. Our preliminary behavioral results showed that there were no significant effects on accuracy (ACC) or reaction time (RT) compared tDCS to sham stimulation. There were also no significant effects on ACC and RT between online or offline stimulation and no significant effects in the interaction of these variables (p > 0.05). Conclusion. In summary, our study demonstrates that multichannel tDCS over DLPFC with 2 mA intensity over 20 min is well tolerated, and thus may be used as an experimental and treatment method in the pediatric population. Based on preliminary behavioral data, we could not show any stimulation effect. In accordance to literature though, stimulation often shows bigger effects on clinical population rather than healthy participants. Possible reasons for null findings could be ceiling effects (e.g. Suitability of the Paradigm depending on age). Furthermore, individual differences like baseline activity, may have had an impact on stimulation effectivity. Additional EEG analysis may provide more specific insights into developmental aspects of working memory processing on the neural level.

Background Body mass index (BMI) and adult height are moderately and highly heritable traits, respectively. To investigate the genetic background of these quantitative phenotypes, we performed a linkage genome scan in the extended pedigrees of the Framingham Heart Study. Two variance-components approaches (SOLAR and MERLIN-VC) and one regression method (MERLIN-REGRESS) were applied to the data. Results Evidence for linkage to BMI was found on chromosomes 16 and 6 with maximum LOD scores of 3.2 and 2.7, respectively. For height, all markers showing a LOD score greater than 1 in our analysis correspond to previously reported linkage regions, including chromosome 6q with a maximum LOD score of 2.45 and chromosomes 9, 12, 14, 18, and 22. Regarding the analysis, the three applied methods gave very similar results in this unselected sample with approximately normally distributed traits. Conclusion Our analysis resulted in the successful identification of linked regions. In particular, we consider the regions on chromosomes 6 and 16 for BMI and the regions on chromosomes 6, 9, and 12 for stature interesting for fine mapping and candidate gene studies.