| 1 | Biochem. Soc. Trans. 2010 Apr 38: 445-51 |
|---|---|
| PMID | 20298200 |
| Title | Confirmed rare copy number variants implicate novel genes in schizophrenia. |
| Abstract | Understanding how cognitive processes including learning, memory, decision making and ideation are encoded by the genome is a key question in biology. Identification of sets of genes underlying human mental disorders is a path towards this objective. schizophrenia is a common disease with cognitive symptoms, high heritability and complex genetics. We have identified genes involved with schizophrenia by measuring differences in DNA copy number across the entire genome in 91 schizophrenia cases and 92 controls in the Scottish population. Our data reproduce rare and common variants observed in public domain data from >3000 schizophrenia cases, confirming known disease loci as well as identifying novel loci. We found copy number variants in PDE10A (phosphodiesterase 10A), CYFIP1 [cytoplasmic FMR1 (Fragile X mental retardation 1)-interacting protein 1], K(+) channel genes KCNE1 and KCNE2, the Down's syndrome critical region 1 gene RCAN1 (regulator of calcineurin 1), cell-recognition protein CHL1 (cell adhesion molecule with homology with L1CAM), the transcription factor SP4 (specificity protein 4) and histone deacetylase HDAC9, among others (see http://www.genes2cognition.org/SCZ-CNV). Integrating the function of these many genes into a coherent model of schizophrenia and cognition is a major unanswered challenge. |
| SCZ Keywords | schizophrenia |
| 2 | Neuron 2013 Sep 79: 1169-82 |
| PMID | 24050404 |
| Title | CYFIP1 coordinates mRNA translation and cytoskeleton remodeling to ensure proper dendritic spine formation. |
| Abstract | The CYFIP1/SRA1 gene is located in a chromosomal region linked to various neurological disorders, including intellectual disability, autism, and schizophrenia. CYFIP1 plays a dual role in two apparently unrelated processes, inhibiting local protein synthesis and favoring actin remodeling. Here, we show that brain-derived neurotrophic factor (BDNF)-driven synaptic signaling releases CYFIP1 from the translational inhibitory complex, triggering translation of target mRNAs and shifting CYFIP1 into the WAVE regulatory complex. Active Rac1 alters the CYFIP1 conformation, as demonstrated by intramolecular FRET, and is key in changing the equilibrium of the two complexes. CYFIP1 thus orchestrates the two molecular cascades, protein translation and actin polymerization, each of which is necessary for correct spine morphology in neurons. The CYFIP1 interactome reveals many interactors associated with brain disorders, opening new perspectives to define regulatory pathways shared by neurological disabilities characterized by spine dysmorphogenesis. |
| SCZ Keywords | schizophrenia |
| 3 | World J Psychiatry 2013 Sep 3: 57-61 |
| PMID | 24255876 |
| Title | New findings in the genetics of schizophrenia. |
| Abstract | New findings in schizophrenia genetics are based on genome-wide association studies (GWAS), research into DNA copy number variations (CNVs), and endophenotypes. More than 70 genes have recently been suspected to be involved in the genetic background of schizophrenia based on the GWAS´s results. They are typically related to neurodevelopment/neuroplasticity, immunology and neuroendocrinology. Nevertheless, for many detected genes their possible relationship to schizophrenia etiopathogenesis is still unknown. The CNVs at genome loci 1q21.1 (candidate gene e.g., PRKAB2), 2p16.3 (candidate gene e.g., NRXN1), 3q29 (candidate genes e.g., BDH1, DLG1, PAK2 or TFRC), 15q11.2 (candidate gene e.g., CYFIP1), 15q13.3 (candidate gene e.g., CHRNA7), 16p13.1 (candidate genes e.g.,NTAN1 or NDE1) and 22q11.2 (candidate genes e.g., COMT, GSTT2 or PRODH) were associated with schizophrenia most frequently. Genetic research of schizophrenia endophenotypes, usually neurophysiological, neuromotoric, neurocognitive, neuroanatomical, neurological or personality-related, will help us to discover the role of relevant genes in the pathogenesis of schizophrenia. It is also necessary to integrate knowledge from other research platforms in schizophrenia, like epigenetics, studies of gene-environment interactions, transcriptomics, proteomics, metabolomics, neuroimaging and psychopathology. A better knowledge of the genetic background of schizophrenia can lead to changes in the treatment, prevention and genetic counselling. It may also reduce stigma in this severe mental disorder. |
| SCZ Keywords | schizophrenia |
| 4 | Am. J. Med. Genet. A 2013 Nov 161A: 2846-54 |
| PMID | 24123946 |
| Title | Genetic counseling for susceptibility loci and neurodevelopmental disorders: the del15q11.2 as an example. |
| Abstract | In recent years, several recurrent copy number variations (CNVs) that confer risk of neurodevelopmental disorders have been identified (e.g., del and dup 16p11.2, del15q13.3, del and dup 1q21.1, del16p13.3, del15q11.2). They are often inherited from an unaffected parent and lack phenotypic specificity. Although there is growing evidence from association studies to consider them as susceptibility CNVs, their clinical utility is debated. Yet the clinician is frequently challenged to deal with these counseling situations without guidelines or consensus. In this report, counseling issues and research opportunities are discussed, with the recurrent 15q11.2 BP1-BP2 (including CYFIP1, NIPA1, NIPA2, TUBGCP5) as an example. Several clinical reports have been published describing patients with del15q11.2 featuring intellectual disability, developmental delay, neurological problems, autism spectrum disorder (ASD), attention problems, speech delay, and dysmorphism. The del15q11.2 was found to be significantly associated with intellectual disability, schizophrenia, epilepsy, and ASD. In this report we discuss how patient-specific and family-specific information may alter the interpretation of del15q11.2 as a contributing factor to the disorder in practical counseling situations. In addition, an association study for ASD in a Belgian Flemish cohort and an overview of reported association studies, clinical reports and genomics data for del15q11.2 are presented. |
| SCZ Keywords | schizophrenia |
| 5 | Schizophr Bull 2013 May 39: 712-9 |
| PMID | 22317777 |
| Title | Rare CNVs and tag SNPs at 15q11.2 are associated with schizophrenia in the Han Chinese population. |
| Abstract | Rare copy number variations (CNVs) were involved in the etiology of neuropsychiatric disorders, and some of them appeared to be shared risk factors for several different diseases. One of those promising loci is the CNV at 15q11.2, including 4 genes, TUBGCP5, CYFIP1, NIPA2, and NIPA1. Several studies showed that microdeletions at this locus were significant associated with schizophrenia. In the current study, we investigated the role of both rare CNVs and common single nucleotide polymorphisms (SNPs) at 15q11.2 in schizophrenia in the Chinese Han population. We screened deletions at 15q11.2 in 2058 schizophrenia patients and 3275 normal controls in Chinese Han population by Affymetrix 500K/6.0 SNP arrays and SYBR green real-time polymerase chain reaction and then validated deletions by multiplex ligation-dependent probe amplification and Taqman real-time assays. We successfully genotyped 27 tag SNPs in total and tested associations in 1144 schizophrenia cases and 1144 normal controls. We found a triple increase of deletions in cases over controls, with OR=4.45 (95% CI=1.36-14.60) and P=.014. In the analysis of common SNPs, we found that the most significant SNP in schizophrenia was rs4778334 (OR=.72, 95% CI=0.60-0.87, allelic P=.0056 after permutation, genotypic P=.015 after permutation). We also found SNP rs1009153 in CYFIP1 was associated with schizophrenia (OR=0.82, 95% CI=0.73-0.93, allelic P=.044 after permutation). We found that both rare deletions and common variants at 15q11.2 were associated with schizophrenia in the Chinese Han population. |
| SCZ Keywords | schizophrenia |
| 6 | Schizophr Bull 2014 Nov 40: 1285-99 |
| PMID | 24664977 |
| Title | Systematic prioritization and integrative analysis of copy number variations in schizophrenia reveal key schizophrenia susceptibility genes. |
| Abstract | schizophrenia is a common mental disorder with high heritability and strong genetic heterogeneity. Common disease-common variants hypothesis predicts that schizophrenia is attributable in part to common genetic variants. However, recent studies have clearly demonstrated that copy number variations (CNVs) also play pivotal roles in schizophrenia susceptibility and explain a proportion of missing heritability. Though numerous CNVs have been identified, many of the regions affected by CNVs show poor overlapping among different studies, and it is not known whether the genes disrupted by CNVs contribute to the risk of schizophrenia. By using cumulative scoring, we systematically prioritized the genes affected by CNVs in schizophrenia. We identified 8 top genes that are frequently disrupted by CNVs, including NRXN1, CHRNA7, BCL9, CYFIP1, GJA8, NDE1, SNAP29, and GJA5. Integration of genes affected by CNVs with known schizophrenia susceptibility genes (from previous genetic linkage and association studies) reveals that many genes disrupted by CNVs are also associated with schizophrenia. Further protein-protein interaction (PPI) analysis indicates that protein products of genes affected by CNVs frequently interact with known schizophrenia-associated proteins. Finally, systematic integration of CNVs prioritization data with genetic association and PPI data identifies key schizophrenia candidate genes. Our results provide a global overview of genes impacted by CNVs in schizophrenia and reveal a densely interconnected molecular network of de novo CNVs in schizophrenia. Though the prioritized top genes represent promising schizophrenia risk genes, further work with different prioritization methods and independent samples is needed to confirm these findings. Nevertheless, the identified key candidate genes may have important roles in the pathogenesis of schizophrenia, and further functional characterization of these genes may provide pivotal targets for future therapeutics and diagnostics. |
| SCZ Keywords | schizophrenia |
| 7 | Transl Psychiatry 2014 -1 4: e374 |
| PMID | 24667445 |
| Title | The autism and schizophrenia associated gene CYFIP1 is critical for the maintenance of dendritic complexity and the stabilization of mature spines. |
| Abstract | Copy number variation (CNV) at the 15q11.2 region has been identified as a significant risk locus for neurological and neuropsychiatric conditions such as schizophrenia (SCZ) and autism spectrum disorder (ASD). However, the individual roles for genes at this locus in nervous system development, function and connectivity remain poorly understood. Haploinsufficiency of one gene in this region, CYFIP1, may provide a model for 15q11.2 CNV-associated neuropsychiatric phenotypes. Here we show that altering CYFIP1 expression levels in neurons both in vitro and in vivo influences dendritic complexity, spine morphology, spine actin dynamics and synaptic ?-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor lateral diffusion. CYFIP1 is highly enriched at synapses and its overexpression in vitro leads to increased dendritic complexity. Neurons derived from CYFIP1 heterozygous animals on the other hand, possess reduced dendritic complexity, increased mobile F-actin and enhanced GluA2-containing AMPA receptor mobility at synapses. Interestingly, CYFIP1 overexpression or haploinsufficiency increased immature spine number, whereas activity-dependent changes in spine volume were occluded in CYFIP1 haploinsufficient neurons. In vivo, CYFIP1 heterozygous animals exhibited deficits in dendritic complexity as well as an altered ratio of immature-to-mature spines in hippocampal CA1 neurons. In summary, we provide evidence that dysregulation of CYFIP1 expression levels leads to pathological changes in CNS maturation and neuronal connectivity, both of which may contribute to the development of the neurological symptoms seen in ASD and SCZ. |
| SCZ Keywords | schizophrenia |
| 8 | Cell Stem Cell 2014 Jul 15: 79-91 |
| PMID | 24996170 |
| Title | Modeling a genetic risk for schizophrenia in iPSCs and mice reveals neural stem cell deficits associated with adherens junctions and polarity. |
| Abstract | Defects in brain development are believed to contribute toward the onset of neuropsychiatric disorders, but identifying specific underlying mechanisms has proven difficult. Here, we took a multifaceted approach to investigate why 15q11.2 copy number variants are prominent risk factors for schizophrenia and autism. First, we show that human iPSC-derived neural progenitors carrying 15q11.2 microdeletion exhibit deficits in adherens junctions and apical polarity. This results from haploinsufficiency of CYFIP1, a gene within 15q11.2 that encodes a subunit of the WAVE complex, which regulates cytoskeletal dynamics. In developing mouse cortex, deficiency in CYFIP1 and WAVE signaling similarly affects radial glial cells, leading to their ectopic localization outside of the ventricular zone. Finally, targeted human genetic association analyses revealed an epistatic interaction between CYFIP1 and WAVE signaling mediator ACTR2 and risk for schizophrenia. Our findings provide insight into how CYFIP1 regulates neural stem cell function and may contribute to the susceptibility of neuropsychiatric disorders. |
| SCZ Keywords | schizophrenia |
| 9 | Proc. Natl. Acad. Sci. U.S.A. 2014 Jan 111: 361-6 |
| PMID | 24368850 |
| Title | Ohnologs are overrepresented in pathogenic copy number mutations. |
| Abstract | A number of rare copy number variants (CNVs), including both deletions and duplications, have been associated with developmental disorders, including schizophrenia, autism, intellectual disability, and epilepsy. Pathogenicity may derive from dosage sensitivity of one or more genes contained within the CNV locus. To understand pathophysiology, the specific disease-causing gene(s) within each CNV need to be identified. In the present study, we test the hypothesis that ohnologs (genes retained after ancestral whole-genome duplication events, which are frequently dosage sensitive) are overrepresented in pathogenic CNVs. We selected three sets of genes implicated in copy number pathogenicity: (i) genes mapping within rare disease-associated CNVs, (ii) genes within de novo CNVs under negative genetic selection, and (iii) genes identified by clinical array comparative genome hybridization studies as potentially pathogenic. We compared the proportion of ohnologs between these gene sets and control genes, mapping to CNVs not known to be disease associated. We found that ohnologs are significantly overrepresented in genes mapping to pathogenic CNVs, irrespective of how CNVs were identified, with over 90% containing an ohnolog, compared with control CNVs >100 kb, where only about 30% contained an ohnolog. In some CNVs, such as del15p11.2 (CYFIP1) and dup/del16p13.11 (NDE1), the most plausible prior candidate gene was also an ohnolog, as were the genes VIPR2 and NRXN1, each found in short CNVs containing no other genes. Our results support the hypothesis that ohnologs represent critical dosage-sensitive elements of the genome, possibly responsible for some of the deleterious phenotypes observed for pathogenic CNVs and as such are readily identifiable candidate genes for further study. |
| SCZ Keywords | schizophrenia |
| 10 | Mol. Psychiatry 2015 Sep 20: 1069-78 |
| PMID | 25311365 |
| Title | Increased CYFIP1 dosage alters cellular and dendritic morphology and dysregulates mTOR. |
| Abstract | Rare maternally inherited duplications at 15q11-13 are observed in ~1% of individuals with an autism spectrum disorder (ASD), making it among the most common causes of ASD. 15q11-13 comprises a complex region, and as this copy number variation encompasses many genes, it is important to explore individual genotype-phenotype relationships. Cytoplasmic FMR1-interacting protein 1 (CYFIP1) is of particular interest because of its interaction with Fragile X mental retardation protein (FMRP), its upregulation in transformed lymphoblastoid cell lines from patients with duplications at 15q11-13 and ASD and the presence of smaller overlapping deletions of CYFIP1 in patients with schizophrenia and intellectual disability. Here, we confirm that CYFIP1 is upregulated in transformed lymphoblastoid cell lines and demonstrate its upregulation in the post-mortem brain from 15q11-13 duplication patients for the first time. To investigate how increased CYFIP1 dosage might predispose to neurodevelopmental disease, we studied the consequence of its overexpression in multiple systems. We show that overexpression of CYFIP1 results in morphological abnormalities including cellular hypertrophy in SY5Y cells and differentiated mouse neuronal progenitors. We validate these results in vivo by generating a BAC transgenic mouse, which overexpresses CYFIP1 under the endogenous promotor, observing an increase in the proportion of mature dendritic spines and dendritic spine density. Gene expression profiling on embryonic day 15 suggested the dysregulation of mammalian target of rapamycin (mTOR) signaling, which was confirmed at the protein level. Importantly, similar evidence of mTOR-related dysregulation was seen in brains from 15q11-13 duplication patients with ASD. Finally, treatment of differentiated mouse neuronal progenitors with an mTOR inhibitor (rapamycin) rescued the morphological abnormalities resulting from CYFIP1 overexpression. Together, these data show that CYFIP1 overexpression results in specific cellular phenotypes and implicate modulation by mTOR signaling, further emphasizing its role as a potential convergent pathway in some forms of ASD. |
| SCZ Keywords | schizophrenia |
| 11 | Mol Neuropsychiatry 2015 Jul 1: 116-123 |
| PMID | 26528485 |
| Title | Genetic and morphological features of human iPSC-derived neurons with chromosome 15q11.2 (BP1-BP2) deletions. |
| Abstract | Copy number variation on chromosome 15q11.2 (BP1-BP2) causes deletion of CYFIP1, NIPA1, NIPA2 and TUBGCP5; it also affects brain structure and elevates risk for several neurodevelopmental disorders that are associated with dendritic spine abnormalities. In rodents, altered CYFIP1 expression changes dendritic spine morphology, motivating analyses of human neuronal cells derived from iPSCs (iPSC-neurons). iPSCs were generated from a mother and her offspring, both carrying the 15q11.2 (BP1-BP2) deletion, and a non-deletion control. Gene expression in the deletion region was estimated using quantitative real-time PCR assays. Neural progenitor cells (NPCs) and iPSC-neurons were characterized using immunocytochemistry. CYFIP1, NIPA1, NIPA2 and TUBGCP5 gene expression was lower in iPSCs, NPCs and iPSC-neurons from the mother and her offspring in relation to control cells. CYFIP1 and PSD95 protein levels were lower in iPSC-neurons derived from the CNV bearing individuals using Western blot analysis. At 10 weeks post-differentiation, iPSC-neurons appeared to show dendritic spines and qualitative analysis suggested that dendritic morphology was altered in 15q11.2 deletion subjects compared with control cells. The 15q11.2 (BP1-BP2) deletion is associated with reduced expression of four genes in iPSC-derived neuronal cells; it may also be associated altered iPSC-neuron dendritic morphology. |
| SCZ Keywords | schizophrenia |
| 12 | Int J Mol Sci 2015 -1 16: 4068-82 |
| PMID | 25689425 |
| Title | The 15q11.2 BP1-BP2 microdeletion syndrome: a review. |
| Abstract | Patients with the 15q11.2 BP1-BP2 microdeletion can present with developmental and language delay, neurobehavioral disturbances and psychiatric problems. Autism, seizures, schizophrenia and mild dysmorphic features are less commonly seen. The 15q11.2 BP1-BP2 microdeletion involving four genes (i.e., TUBGCP5, CYFIP1, NIPA1, NIPA2) is emerging as a recognized syndrome with a prevalence ranging from 0.57%-1.27% of patients presenting for microarray analysis which is a two to four fold increase compared with controls. Review of clinical features from about 200 individuals were grouped into five categories and included developmental (73%) and speech (67%) delays; dysmorphic ears (46%) and palatal anomalies (46%); writing (60%) and reading (57%) difficulties, memory problems (60%) and verbal IQ scores ?75 (50%); general behavioral problems, unspecified (55%) and abnormal brain imaging (43%). Other clinical features noted but not considered as common were seizures/epilepsy (26%), autism spectrum disorder (27%), attention deficit disorder (ADD)/attention deficit hyperactivity disorder (ADHD) (35%), schizophrenia/paranoid psychosis (20%) and motor delay (42%). Not all individuals with the deletion are clinically affected, yet the collection of findings appear to share biological pathways and presumed genetic mechanisms. Neuropsychiatric and behavior disturbances and mild dysmorphic features are associated with genomic imbalances of the 15q11.2 BP1-BP2 region, including microdeletions, but with an apparent incomplete penetrance and variable expressivity. |
| SCZ Keywords | schizophrenia |
| 13 | PLoS ONE 2016 -1 11: e0148039 |
| PMID | 26824476 |
| Title | Reduced CYFIP1 in Human Neural Progenitors Results in Dysregulation of Schizophrenia and Epilepsy Gene Networks. |
| Abstract | Deletions encompassing the BP1-2 region at 15q11.2 increase schizophrenia and epilepsy risk, but only some carriers have either disorder. To investigate the role of CYFIP1, a gene within the region, we performed knockdown experiments in human neural progenitors derived from donors with 2 copies of each gene at the BP1-2 locus. RNA-seq and cellular assays determined that knockdown of CYFIP1 compromised cytoskeletal remodeling. FMRP targets and postsynaptic density genes, each implicated in schizophrenia, were significantly overrepresented among differentially expressed genes (DEGs). schizophrenia and/or epilepsy genes, but not those associated with randomly selected disorders, were likewise significantly overrepresented. Mirroring the variable expressivity seen in deletion carriers, marked between-line differences were observed for dysregulation of disease genes. Finally, a subset of DEGs showed a striking similarity to known epilepsy genes and represents novel disease candidates. Results support a role for CYFIP1 in disease and demonstrate that disease-related biological signatures are apparent prior to neuronal differentiation. |
| SCZ Keywords | schizophrenia |
| 14 | J. Neurosci. 2016 Feb 36: 1564-76 |
| PMID | 26843638 |
| Title | Cyfip1 Regulates Presynaptic Activity during Development. |
| Abstract | Copy number variations encompassing the gene encoding CYFIP1 have been associated with a variety of human diseases, including autism and schizophrenia. Here we show that juvenile mice hemizygous for CYFIP1 have altered presynaptic function, enhanced protein translation, and increased levels of F-actin. In developing hippocampus, reduced CYFIP1 levels serve to decrease paired pulse facilitation and increase miniature EPSC frequency without a change in amplitude. Higher-resolution examination shows these changes to be caused primarily by an increase in presynaptic terminal size and enhanced vesicle release probability. Short hairpin-mediated knockdown of CYFIP1 coupled with expression of mutant CYFIP1 proteins indicates that the presynaptic alterations are caused by dysregulation of the WAVE regulatory complex. Such dysregulation occurs downstream of Rac1 as acute exposure to Rac1 inhibitors rescues presynaptic responses in culture and in hippocampal slices. The data serve to highlight an early and essential role for CYFIP1 in the generation of normally functioning synapses and suggest a means by which changes in CYFIP1 levels could impact the generation of neural networks and contribute to abnormal and maladaptive behaviors. Several developmental brain disorders have been associated with gene duplications and deletions that serve to increase or decrease levels of encoded proteins. CYFIP1 is one such protein, but the role it plays in brain development is poorly understood. We asked whether decreased CYFIP1 levels altered the function of developing synapses. The data show that synapses with reduced CYFIP1 are larger and release neurotransmitter more rapidly. These effects are due to CYFIP1's role in actin polymerization and are reversed by expression of a CYFIP1 mutant protein retaining actin regulatory function or by inhibiting Rac1. Thus, CYFIP1 has a more prominent early role regulating presynaptic activity during a stage of development when activity helps to define neural pathways. |
| SCZ Keywords | schizophrenia |