Behavioral changes and growth deficits in a CRISPR engineered mouse model of the schizophrenia-associated 3q29 deletion.

The 3q29 deletion confers increased risk for neuropsychiatric phenotypes including intellectual disability, autism spectrum disorder, generalized anxiety disorder, and a >40-fold increased risk for schizophrenia. To investigate consequences of the 3q29 deletion in an experimental system, we used CRISPR/Cas9 technology to introduce a heterozygous deletion into the syntenic interval on C57BL/6 mouse chromosome 16. mRNA abundance for 20 of the 21 genes in the interval was reduced by ~50%, while protein levels were reduced for only a subset of these, suggesting a compensatory mechanism. Mice harboring the deletion manifested behavioral impairments in multiple domains including social interaction, cognitive function, acoustic startle, and amphetamine sensitivity, with some sex-dependent manifestations. In addition, 3q29 deletion mice showed reduced body weight throughout development consistent with the phenotype of 3q29 deletion syndrome patients. Of the genes within the interval, DLG1 has been hypothesized as a contributor to the neuropsychiatric phenotypes. However, we show that Dlg1+/- mice did not exhibit the behavioral deficits seen in mice harboring the full 3q29 deletion. These data demonstrate the following: the 3q29 deletion mice are a valuable experimental system that can be used to interrogate the biology of 3q29 deletion syndrome; behavioral manifestations of the 3q29 deletion may have sex-dependent effects; and mouse-specific behavior phenotypes associated with the 3q29 deletion are not solely due to haploinsufficiency of Dlg1.

Deep phenotyping in 3q29 deletion syndrome: recommendations for clinical care.

PURPOSE: To understand the consequences of the 3q29 deletion on medical, neurodevelopmental, psychiatric, brain structural, and neurological sequalae by systematic evaluation of affected individuals. To develop evidence-based recommendations using these data for effective clinical care. METHODS: Thirty-two individuals with the 3q29 deletion were evaluated using a defined phenotyping protocol and standardized data collection instruments. RESULTS: Medical manifestations were varied and reported across nearly every organ system. The most severe manifestations were congenital heart defects (25%) and the most common were gastrointestinal symptoms (81%). Physical examination revealed a high proportion of musculoskeletal findings (81%). Neurodevelopmental phenotypes represent a significant burden and include intellectual disability (34%), autism spectrum disorder (38%), executive function deficits (46%), and graphomotor weakness (78%). Psychiatric illness manifests across the lifespan with psychosis prodrome (15%), psychosis (20%), anxiety disorders (40%), and attention deficit-hyperactivity disorder (ADHD) (63%). Neuroimaging revealed structural anomalies of the posterior fossa, but on neurological exam study subjects displayed only mild or moderate motor vulnerabilities. CONCLUSION: By direct evaluation of 3q29 deletion study subjects, we document common features of the syndrome, including a high burden of neurodevelopmental and neuropsychiatric phenotypes. Evidence-based recommendations for evaluation, referral, and management are provided to help guide clinicians in the care of 3q29 deletion patients.

Craniofacial features of 3q29 deletion syndrome: Application of next-generation phenotyping technology.

3q29 deletion syndrome (3q29del) is a recurrent deletion syndrome associated with neuropsychiatric disorders and congenital anomalies. Dysmorphic facial features have been described but not systematically characterized. This study aims to detail the 3q29del craniofacial phenotype and use a machine learning approach to categorize individuals with 3q29del through analysis of 2D photos. Detailed dysmorphology exam and 2D facial photos were ascertained from 31 individuals with 3q29del. Photos were used to train the next-generation phenotyping algorithm DeepGestalt (Face2Gene by FDNA, Inc, Boston, MA) to distinguish 3q29del cases from controls and all other recognized syndromes. Area under the curve of receiver operating characteristic curves (AUC-ROC) was used to determine the capacity of Face2Gene to identify 3q29del cases against controls. In this cohort, the most common observed craniofacial features were prominent forehead (48.4%), prominent nose tip (35.5%), and thin upper lip vermillion (25.8%). The FDNA technology showed an ability to distinguish cases from controls with an AUC-ROC value of 0.873 (p = 0.006) and led to the inclusion of 3q29del as one of the supported syndromes. This study found a recognizable facial pattern in 3q29del, as observed by trained clinical geneticists and next-generation phenotyping technology. These results expand the potential application of automated technology such as FDNA in identifying rare genetic syndromes, even when facial dysmorphology is subtle.

Comprehensive phenotyping of neuropsychiatric traits in a multiplex 3q29 deletion family: a case report.

BACKGROUND: 3q29 deletion syndrome is associated with a range of medical, neurodevelopmental, and psychiatric phenotypes. The deletion is usually de novo but cases have been reported where the deletion is inherited from apparently unaffected parents. The presence of these unaffected or mildly affected individuals suggests there may be an ascertainment bias for severely affected cases of 3q29 deletion syndrome, thus the more deleterious consequence of the 3q29 deletion may be overestimated. However, a substantial fraction of 3q29 deletion syndrome morbidity is due to psychiatric illness. In many case reports, probands and transmitting parents are not systematically evaluated for psychiatric traits. Here we report results from a systematic phenotyping protocol for neurodevelopmental and neuropsychiatric traits applied to all 3q29 deletion carriers in a multiplex family. CASE PRESENTATION: Through the 3q29 registry at Emory University, a multiplex family was identified where three offspring had a paternally inherited 3q29 deletion. We evaluated all 4 3q29 deletion family members using our previously described standardized, systematic phenotyping protocol. The transmitting parent reported no psychiatric history, however upon evaluation he was discovered to meet criteria for multiple psychiatric diagnoses including previously undiagnosed schizoaffective disorder. All four 3q29 deletion individuals in the pedigree had multiple psychiatric diagnoses that interfered with quality of life and prohibited successful academic and occupational functioning. Cognitive ability for all individuals was average or below average, but within the normal range. CONCLUSIONS: This is the first case report of inherited 3q29 deletion syndrome where all affected individuals in the pedigree have been comprehensively and systematically evaluated for neurodevelopmental and psychiatric symptoms, using a standard battery of normed instruments administered by expert clinicians. Our investigation reveals that individuals with 3q29 deletion syndrome may have psychiatric morbidity that is debilitating, but only apparent through specialized evaluation by an expert. In the absence of appropriate evaluation, individuals with 3q29 deletion syndrome may suffer from psychiatric illness but lack avenues for access to care. The individuals evaluated here all have cognition in the normal range alongside multiple psychiatric diagnoses each, suggesting that cognitive ability alone is not a representative proxy for 3q29 deletion-associated disability. These results require replication in a larger cohort of individuals with 3q29 deletion syndrome.

Study protocol for The Emory 3q29 Project: evaluation of neurodevelopmental, psychiatric, and medical symptoms in 3q29 deletion syndrome.

BACKGROUND: 3q29 deletion syndrome is caused by a recurrent hemizygous 1.6 Mb deletion on the long arm of chromosome 3. The syndrome is rare (1 in 30,000 individuals) and is associated with mild to moderate intellectual disability, increased risk for autism and anxiety, and a 40-fold increased risk for schizophrenia, along with a host of physical manifestations. However, the disorder is poorly characterized, the range of manifestations is not well described, and the underlying molecular mechanism is not understood. We designed the Emory 3q29 Project to document the range of neurodevelopmental and psychiatric manifestations associated with 3q29 deletion syndrome. We will also create a biobank of samples from our 3q29 deletion carriers for mechanistic studies, which will be a publicly-available resource for qualified investigators. The ultimate goals of our study are three-fold: first, to improve management and treatment of 3q29 deletion syndrome. Second, to uncover the molecular mechanism of the disorder. Third, to enable cross-disorder comparison with other rare genetic syndromes associated with neuropsychiatric phenotypes. METHODS: We will ascertain study subjects, age 6 and older, from our existing registry ( 3q29deletion.org ). Participants and their families will travel to Atlanta, GA for phenotypic assessments, with particular emphasis on evaluation of anxiety, cognitive ability, autism symptomatology, and risk for psychosis via prodromal symptoms and syndromes. Evaluations will be performed using standardized instruments. Structural, diffusion, and resting-state functional MRI data will be collected from eligible study participants. We will also collect blood from the 3q29 deletion carrier and participating family members, to be banked at the NIMH Repository and Genomics Resource (NRGR). DISCUSSION: The study of 3q29 deletion has the potential to transform our understanding of complex disease. Study of individuals with the deletion may provide insights into long term care and management of the disorder. Our project describes the protocol for a prospective study of the behavioral and clinical phenotype associated with 3q29 deletion syndrome. The paradigm described here could easily be adapted to study additional CNV or single gene disorders with high risk for neuropsychiatric phenotypes, and/or transferred to other study sites, providing a means for data harmonization and cross-disorder analysis.

Microdeletions of 3q29 confer high risk for schizophrenia.

Schizophrenia (SZ) is a severe psychiatric illness that affects approximately 1% of the population and has a strong genetic underpinning. Recently, genome-wide analysis of copy-number variation (CNV) has implicated rare and de novo events as important in SZ. Here, we report a genome-wide analysis of 245 SZ cases and 490 controls, all of Ashkenazi Jewish descent. Because many studies have found an excess burden of large, rare deletions in cases, we limited our analysis to deletions over 500 kb in size. We observed seven large, rare deletions in cases, with 57% of these being de novo. We focused on one 836 kb de novo deletion at chromosome 3q29 that falls within a 1.3-1.6 Mb deletion previously identified in children with intellectual disability (ID) and autism, because increasing evidence suggests an overlap of specific rare copy-number variants (CNVs) between autism and SZ. By combining our data with prior CNV studies of SZ and analysis of the data of the Genetic Association Information Network (GAIN), we identified six 3q29 deletions among 7545 schizophrenic subjects and one among 39,748 controls, resulting in a statistically significant association with SZ (p = 0.02) and an odds ratio estimate of 17 (95% confidence interval: 1.36-1198.4). Moreover, this 3q29 deletion region contains two linkage peaks from prior SZ family studies, and the minimal deletion interval implicates 20 annotated genes, including PAK2 and DLG1, both paralogous to X-linked ID genes and now strong candidates for SZ susceptibility.

Genomic structural variation and schizophrenia.

It has recently been demonstrated that a large amount of structural variation exists in the human genome. Since 2004, when two landmark studies reported polymorphic levels of copy number variation in phenotypically normal individuals, our understanding of genome-wide levels of copy number variation has grown. This has inspired hypotheses about this class of variation's contribution to complex genetic phenotypes, including the specific hypothesis that structural variation is associated with psychiatric illness. The technology to accurately and efficiently detect polymorphic structural variants is still largely under development, but some examples of genomic imbalance contributing to schizophrenia and bipolar disorder already have been identified. Although much optimism surrounds this burgeoning field, the technical challenges in reliably identifying structural variation mean recent literature should be approached with caution.

Reciprocal duplication of the Williams-Beuren syndrome deletion on chromosome 7q11.23 is associated with schizophrenia.

BACKGROUND: Several copy number variants (CNVs) have been implicated as susceptibility factors for schizophrenia (SZ). Some of these same CNVs also increase risk for autism spectrum disorders, suggesting an etiologic overlap between these conditions. Recently, de novo duplications of a region on chromosome 7q11.23 were associated with autism spectrum disorders. The reciprocal deletion of this region causes Williams-Beuren syndrome. METHODS: We assayed an Ashkenazi Jewish cohort of 554 SZ cases and 1014 controls for genome-wide CNV. An excess of large rare and de novo CNVs were observed, including a 1.4 Mb duplication on chromosome 7q11.23 identified in two unrelated patients. To test whether this 7q11.23 duplication is also associated with SZ, we obtained data for 14,387 SZ cases and 28,139 controls from seven additional studies with high-resolution genome-wide CNV detection. We performed a meta-analysis, correcting for study population of origin, to assess whether the duplication is associated with SZ. RESULTS: We found duplications at 7q11.23 in 11 of 14,387 SZ cases with only 1 in 28,139 control subjects (unadjusted odds ratio 21.52, 95% confidence interval: 3.13-922.6, p value 5.5 × 10(-5); adjusted odds ratio 10.8, 95% confidence interval: 1.46-79.62, p value .007). Of three SZ duplication carriers with detailed retrospective data, all showed social anxiety and language delay premorbid to SZ onset, consistent with both human studies and animal models of the 7q11.23 duplication. CONCLUSIONS: We have identified a new CNV associated with SZ. Reciprocal duplication of the Williams-Beuren syndrome deletion at chromosome 7q11.23 confers an approximately tenfold increase in risk for SZ.

Cardiovascular disease, psychosocial factors, and genetics: the case of depression.

Psychosocial factors are associated with cardiovascular disease, but little is known about the role of genetics in this relationship. Focusing on the well-studied phenotype of depression, current data show that there are shared genetic factors that may give rise to both depression and CVD, and these genetic risks appear to be modified by gender. This pleiotropic effect suggests that a single pathway, when perturbed, gives rise to the dual phenotypes of CVD and depression. The data also suggest that women contribute disproportionately to the depression-CVD comorbidity, and this unbalanced contribution is attributable, in part, to genetic factors. While the underlying biology behind this relationship is unclear, recent data support contributions from inflammatory or serotonergic pathways toward the comorbidity between CVD and depression. Even without knowledge of a specific mechanism, epidemiological observations offer new directions to explain the relationship between depression and CVD that have both research and clinical applications.

Schizophrenia genetics: progress, at last.

The heritability of schizophrenia is well established, and has motivated the search for genetic variation that contributes to susceptibility. Recent progress from both genome-wide association and copy number variant studies have identified risk loci, however, these are at very different ends of the susceptibility spectrum with respect to allele frequency and effect size. It is likely that investigations of common variants have surrendered their full yield, but rare variant exploration is at the very beginning.