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Autism is a severe neurodevelopmental disorder, the aetiology of which remains mainly unknown. Family and twin studies provide strong evidence that genetic factors have a major role in the aetiology of this disease. Recently, whole exome sequencing (WES) efforts have focused mainly on rare de novo variants in singleton families. Although these studies have provided pioneering insights, de novo variants probably explain only a small proportion of the autism risk variance. In this study, we performed exome sequencing of 10 autism multiplex families with the aim of investigating the role of rare variants that are coinherited in the affected sibs. The pool of variants selected in our study is enriched with genes involved in neuronal functions or previously reported in psychiatric disorders, as shown by Gene Ontology analysis and by browsing the Neurocarta database. Our data suggest that rare truncating heterozygous variants have a predominant role in the aetiology of autism. Using a multiple linear regression model, we found that the burden of truncating mutations correlates with a lower non-verbal intelligence quotient (NVIQ). Also, the number of truncating mutations that were transmitted to the affected sibs was significantly higher (twofold) than those not transmitted. Protein-protein interaction analysis performed with our list of mutated genes revealed that the postsynaptic YWHAZ is the most interconnected node of the network. Among the genes found disrupted in our study, there is evidence suggesting that YWHAZ and also the X-linked DRP2 may be considered as novel autism candidate genes. [ABSTRACT FROM AUTHOR]

Cocaine dependence is a neuropsychiatric disorder in which both environmental and genetic factors are involved. Several processes, that include reward and neuroadaptations, mediate the transition from use to dependence. In this regard, dopamine and serotonin neurotransmission systems are clearly involved in reward and other cocaine-related effects, whereas neurotrophic factors may be responsible for neuroadaptations associated with cocaine dependence. We examined the contribution to cocaine dependence of 37 genes related to the dopaminergic and serotoninergic systems, neurotrophic factors and their receptors through a case-control association study with 319 single nucleotide polymorphisms selected according to genetic coverage criteria in 432 cocaine-dependent patients and 482 sex-matched unrelated controls. Single marker analyses provided evidence for association of the serotonin receptor HTR2A with cocaine dependence [rs6561333; nominal P-value adjusted for age = 1.9e−04, odds ratio = 1.72 (1.29-2.30)]. When patients were subdivided according to the presence or absence of psychotic symptoms, we confirmed the association between cocaine dependence and HTR2A in both subgroups of patients. Our data show additional evidence for the involvement of the serotoninergic system in the genetic susceptibility to cocaine dependence. [ABSTRACT FROM AUTHOR]

The adult form of attention deficit/hyperactivity disorder (aADHD) has a prevalence of up to 5% and is the most severe long-term outcome of this common neurodevelopmental disorder. Family studies in clinical samples suggest an increased familial liability for aADHD compared with childhood ADHD (cADHD), whereas twin studies based on self-rated symptoms in adult population samples show moderate heritability estimates of 30-40%. However, using multiple sources of information, the heritability of clinically diagnosed aADHD and cADHD is very similar. Results of candidate gene as well as genome-wide molecular genetic studies in aADHD samples implicate some of the same genes involved in ADHD in children, although in some cases different alleles and different genes may be responsible for adult versus childhood ADHD. Linkage studies have been successful in identifying loci for aADHD and led to the identification of LPHN3 and CDH13 as novel genes associated with ADHD across the lifespan. In addition, studies of rare genetic variants have identified probable causative mutations for aADHD. Use of endophenotypes based on neuropsychology and neuroimaging, as well as next-generation genome analysis and improved statistical and bioinformatic analysis methods hold the promise of identifying additional genetic variants involved in disease etiology. Large, international collaborations have paved the way for well-powered studies. Progress in identifying aADHD risk genes may provide us with tools for the prediction of disease progression in the clinic and better treatment, and ultimately may help to prevent persistence of ADHD into adulthood. [ABSTRACT FROM AUTHOR]

3,4-Methylenedioxymethamphetamine (MDMA, 'ecstasy') is a recreational drug widely used by adolescents and young adults. Although its rewarding effects are well established, there is controversy on its addictive potential. We aimed to compare the consequences of active and passive MDMA administration on gene expression in the mouse brain since all previous studies were based on passive MDMA administration. We used a yoked-control operant intravenous self-administration paradigm combined with microarray technology. Transcriptomic profiles of ventral striatum, frontal cortex, dorsal raphe nucleus and hippocampus were analysed in mice divided in contingent MDMA, yoked MDMA and yoked saline groups, and several changes were validated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The comparison of contingent MDMA and yoked MDMA vs. yoked saline mice allowed the identification of differential expression in several genes, most of them with immunological and inflammatory functions, but others being involved in neuroadaptation. In the comparison of contingent MDMA vs. yoked MDMA administration, hippocampus and the dorsal raphe nucleus showed statistically significant changes. The altered expression of several genes involved in neuroadaptative changes and synapse function, which may be related to learning self-administration behaviour, could be validated in these two brain structures. In conclusion, our study shows a strong effect of MDMA administration on the expression of immunological and inflammatory genes in all the four brain regions studied. In addition, experiments on MDMA self-administration suggest that the dorsal raphe nucleus and hippocampus may be involved in active MDMA-seeking behaviour, and show specific alterations on gene expression that support the addictive potential of this drug. [ABSTRACT FROM AUTHOR]

Attention deficit hyperactivity disorder (ADHD) is a common behavioral disorder affecting children and adults. It has been suggested that gene variants related to serotonin neurotransmission are associated with ADHD. We tested the functional promoter polymorphism 5-HTTLPR and seven single nucleotide polymorphisms in SLC6A4 for association with ADHD in 448 adult ADHD patients and 580 controls from Norway. Replication attempts were performed in a sample of 1454 Caucasian adult ADHD patients and 1302 controls from Germany, Spain, the Netherlands and USA, and a meta-analysis was performed also including a previously published adult ADHD study. We found an association between ADHD and rs140700 [odds ratio (OR ) = 0.67; P = 0.01] and the short (S) allele of the 5-HTTLPR (OR = 1.19; P = 0.06) in the Norwegian sample. Analysis of a possible gender effect suggested that the association might be restricted to females (rs140700: OR = 0.45; P = 0.00084). However, the meta-analysis of 1894 cases and 1878 controls could not confirm the association for rs140700 [OR = 0.85, 95% confidence interval (CI) = 0.67–1.09; P = 0.20]. For 5-HTTLPR, five of six samples showed a slight overrepresentation of the S allele in patients, but meta-analysis refuted a strong effect (OR = 1.10, 95% CI = 1.00–1.21; P = 0.06). Neither marker showed any evidence of differential effects for ADHD subtype, gender or symptoms of depression/anxiety. In conclusion, our results do not support a major role for SLC6A4 common variants in persistent ADHD, although a modest effect of the 5-HTTLPR and a role for rare variants cannot be excluded. [ABSTRACT FROM AUTHOR]

Attention-deficit/hyperactivity disorder (ADHD) is a common psychiatric disorder in which different genetic and environmental susceptibility factors are involved. Several lines of evidence support the view that at least 30% of ADHD patients diagnosed in childhood continue to suffer the disorder during adulthood and that genetic risk factors may play an essential role in the persistence of the disorder throughout lifespan. Genetic, biochemical and pharmacological studies support the idea that the serotonin system participates in the etiology of ADHD. Based on these data, we aimed to analyze single nucleotide polymorphisms across 19 genes involved in the serotoninergic neurotransmission in a clinical sample of 451 ADHD patients (188 adults and 263 children) and 400 controls using a population-based association study. Several significant associations were found after correcting for multiple testing: (1) the DDC gene was strongly associated with both adulthood (P=0.00053; odds ratio (OR)=2.17) and childhood ADHD (P=0.0017; OR=1.90); (2) the MAOB gene was found specifically associated in the adult ADHD sample (P=0.0029; OR=1.90) and (3) the 5HT2A gene showed evidence of association only with the combined ADHD subtype both in adults (P=0.0036; OR=1.63) and children (P=0.0084; OR=1.49). Our data support the contribution of the serotoninergic system in the genetic predisposition to ADHD, identifying common childhood and adulthood ADHD susceptibility factors, associations that are specific to ADHD subtypes and one variant potentially involved in the continuity of the disorder throughout lifespan.Molecular Psychiatry (2009) 14, 71–85; doi:10.1038/sj.mp.4002100; published online 16 October 2007 [ABSTRACT FROM AUTHOR]

Discusses the development of a Walker-Warburg syndrome phenotype through a homozygous nonsense mutation in the Fukutin gene. Development of the cerebral cortex through neural migration; Proliferation of sets of neurons at the subventricular zone; Response of neurons to the stop signals at the cobblestone neocortex.

Background and aims: The aim of this study was to investigate the genetic aetiology of intrahepatic cholestasis of pregnancy (ICP) and the impact of known cholestasis genes (BSEP, FIC1, and MDR3) on the development of this disease. Patients and methods: Sixty nine Finnish ICP patients were prospectively interviewed for a family history of ICP, and clinical features were compared in patients with familial ICP (patients with a positive family history, n = 11) and sporadic patients (patients with no known family history of ICP, n = 58). For molecular genetic analysis, 16 individuals from two independently ascertained Finnish ICP families were genotyped for the flanking markers for BSEP, FIC1, and MDR3. Results: The pedigree structures in 16% (11/69) of patients suggested dominant inheritance. Patients with familial ICP had higher serum aminotransferase levels and o higher recurrence risk (92% v 40%). Both segregation of haplotypes and multipoint linkage analysis excluded BSEP, FIC1, and MDR3 genes in the studied pedigrees. Additionally, the MDR3 gene, previously shown to harbour mutations in ICP patients, was negative for mutations when sequenced in four affected individuals from the two families. Conclusions: These results support the hypothesis that the aetiology of ICP is heterogeneous and that ICP is due to a genetic predisposition in a proportion of patients. The results of molecular genetic analysis further suggest that the previously identified three cholestasis genes are not likely to be implicated in these Finnish ICP families with dominant inheritance. [ABSTRACT FROM AUTHOR]

Mutations in the glucocerebrosidase ( GBA) and prosaposin ( PSAP) genes are responsible for Gaucher disease, the most prevalent sphingolipidosis. Somatic cell hybrid analysis and in situ hybridization experiments have localized the GBA gene to 1q21 and the PSAP gene to 10q21-q22. We performed pairwise and multi-point linkage analyses between the two genes and several highly polymorphic markers from the Généthon human linkage map. Our results show that six markers cosegregate with the GBA gene (Zmax = 8.73 at θ = 0.00 for marker D1S2714) and define a 3.2-cM interval between D1S305 and D1S2624 as the most probable location for the gene. Three of these markers (D1S2777, D1S303, and D1S2140), as well as the gene encoding pyruvate kinase ( PKLR), are contained in a single YAC clone together with the GBA gene. A new polymorphism was identified within the PSAP gene (C16045T) and used for linkage studies. The multi-point analysis places the gene in a 9.8-cM interval between D10S1688 and D10S607. The fine localization of these genes provides a useful tool for cosegregation analysis, indirect molecular diagnosis, and population genetic studies. [ABSTRACT FROM AUTHOR]

Background and purpose: Previous studies concerning the role of hormone receptor genetic variants in migraine have provided conflicting results. The aim of this study was to investigate the role of common polymorphisms in the estrogen receptor gene ( ESR1) and the progesterone receptor gene ( PGR) in the risk for migraine in a Spanish population. Methods: In a case–control study, including 210 Caucasoid migraine patients and 210 controls, we examined association between three single nucleotide polymorphisms in the coding region of ESR1, rs2077642, rs1801132, and rs2228480, and an Alu insertion in PGR, and migraine, migraine without aura or migraine with aura. Genotypic, allelic and reconstructed haplotype distributions were compared. Results: We found no significant differences between cases and controls in the distribution of genotypes or alleles for either polymorphism. No haplotype was over-represented in patients. Conclusions: Our study does not support a major contribution of ESR1 and PGR to the pathogenesis of migraine. [ABSTRACT FROM AUTHOR]

Attention-Deficit/Hyperactivity Disorder (ADHD) and obesity are frequently comorbid, genetically correlated, and share brain substrates. The biological mechanisms driving this association are unclear, but candidate systems, like dopaminergic neurotransmission and circadian rhythm, have been suggested. Our aim was to identify the biological mechanisms underpinning the genetic link betweenADHDand obesitymeasures and investigate associations of overlapping genes with brain volumes. We tested the association of dopaminergic and circadian rhythm gene sets with ADHD, body mass index (BMI), and obesity (using GWAS data of N=53,293, N=681,275, and N=98,697, respectively). We then conducted genome-wide ADHD-BMI and ADHD-obesity genebased meta-analyses, followed by pathway enrichment analyses. Finally, we tested the association of ADHD-BMI overlapping genes with brain volumes (primary GWAS data N=10,720-10,928; replication data N=9,428). The dopaminergic gene set was associated with both ADHD (P=5.81x10-3) and BMI (P=1.63x10-5), the circadian rhythm was associated with BMI (P=1.28x10-3). The genome-wide approach also implicated the dopaminergic system, as the Dopamine-DARPP32 Feedback in cAMP Signaling pathway was enriched in both ADHD-BMI and ADHD-obesity results. The ADHD-BMI overlapping genes were associated with putamen volume (P=7.7x10-3; replication data P=3.9x10-2) - a brain region with volumetric reductions in ADHD and BMI and linked to inhibitory control. Our findings suggest that dopaminergic neurotransmission, partially through DARPP-32-dependent signaling and involving the putamen, is a key player underlying the genetic overlap between ADHD and obesity measures. Uncovering shared etiological factors underlying the frequently observedADHD-obesity comorbiditymay have important implications in terms of prevention and/or efficient treatment of these conditions. [ABSTRACT FROM AUTHOR]

At present, 48 different gene loci have been localised and nine gene mutations have been characterised for non-syndromic hearing impairment. We have identified a large five-generation family with mid-and high-frequency hearing impairment. Family members were considered to be affected only if they had bilateral sensorineural hearing loss below the 90th percentile of an age and sex-dependent control audiometric curve of ISO class B. The inheritance of hearing impairment was autosomal dominant. Of seven affected individuals, six were females and one was male. The hearing loss among affected family members was bilateral, sensorineural and varies from mild to moderate. The type of audiogram was U-shaped. Genetic linkage studies are in progress and our preliminary data show exclusion in chromosome 6, chromosome 11 and chromosome 19 in already known loci for midfrequency hearing impairment. This means, we are mapping a novel locus for autosomal dominant midfrequency hearing impairment. [ABSTRACT FROM AUTHOR]

Three sisters suffering from an unusual form of Gaucher's disease are described. These patients had cardiovascular abnormalities consisting of calcification of the ascending aorta and of the aortic and mitral valves. Neurological findings included ophthalmoplegia and saccadic eye movements in two patients, and tonic-clonic seizures in the third. The three patients died, two of them after having undergone aortic valve replacement. Tissue was obtained from one of the sibs and fibroblast and liver beta-glucocerebrosidase activity was reduced to 4% and 11% of mean normal values. Genotype analysis indicated that the patient was homozygous for the D409H mutation. It is tempting to relate the phenotype of severe cardiac involvement to the D409H/D409H genotype, although further cases will be needed before this association can be confirmed. [ABSTRACT FROM PUBLISHER]

An abstract of the article "Screening of cacna1a and ATP1A2 genes in hemiplegic migraine: clinical, genetic and functional studies" by C. Sintas, O. Carreño, R. Corominas, S. A. Serra, M. Vila, N. Fernández-Castillo, C. Toma, R. Pons, M. Llaneza, M. J. Sobrido and colleagues is presented.

An abstract of the article "A loss-of-function CACNA1A mutation causing benign paroxysmal torticollis of infancy" by M. Vila-Pueyo, C. Sintas, M. Flotats, G. Gené, X. Elorza, J. M. Fernández-Fernández, B. Cormand, and A. Macaya is presented.