James Knowles

In response to recent findings implicating trauma in the phenomenology of psychosis, this study explored interactions between adverse childhood experiences (ACEs) and positive symptoms of psychosis in an understudied patient population, comprising individuals of African and Latino ancestry. Endorsement of ACEs was compared between 90 schizophrenia cases and 240 nonpsychotic controls, matched for ethnicity, gender, and age. Relative to controls, cases reported significantly greater exposure to physical abuse, emotional abuse, sexual abuse, neglect, witnessing domestic violence, and household member incarceration. Analyses further evaluated associations between ACEs and subtypes of hallucinations, delusions, and subjective thought disorder. Among female cases, the number of hallucinatory symptoms present increased with increasing ACE score. Hallucinatory symptoms further correlated with individual ACE items. For instance, third-person voices were more common among women exposed to chi...

The present study examined whether or not there are differential rates of traumatic event exposure and presumed Post-Traumatic Stress Disorder (PTSD) between individuals with OCD without comorbid presumed BDD (OCD-Non-BDD) and individuals with OCD with comorbid presumed BDD (OCD+BDD) within a large cohort of OCD participants (N = 605). Individuals in the OCD+BDD group had significantly higher rates of endorsing at least one lifetime traumatic event and presumed PTSD than individuals with OCD-Non-BDD. Additionally, individuals in the OCD+BDD group with comorbid presumed PTSD had significantly higher rates of major depressive disorder (MDD) and presumed panic disorder (PD). A logistic regression analysis revealed that presumed PTSD significantly predicted the presence of BDD symptoms among individuals who experienced at least one lifetime traumatic event in our sample. These findings suggest that individuals in the OCD+BDD group were more likely to have experienced a traumatic event in their lives, to experience presumed PTSD, and to have MDD and presumed PD than individuals in the OCD-Non-BDD group. Clinical implications and possible mechanistic pathways from trauma exposure to OCD and BDD symptomatology are discussed.

Abstract Many of the characteristics of psychiatric disorders, including their early age of onset, moderate to high prevalence (i.e., 1% for schizophrenia, >15% for major depression), reduced fecundity, and high heritability have led many to speculate on how risk alleles have persisted throughout evolutionary history. While several potential mechanisms for maintaining high allele frequency of risk variants have been hypothesized (e.g., weak positive selection, balancing selection), few have been empirically tested. Given the recent analytic advancements in detecting polygenic adaptation, we systematically evaluated evidence for selection across a total of twenty-five complex traits including ten neuropsychiatric disorders, three personality traits, total intracranial volume, seven subcortical brain structure volume traits, and four complex traits with no known neuropsychiatric associations. We tested each set of trait-associated variants for evidence of classical hard sweeps (i.e., extreme integrated haplotype scores, iHS), partial sweeps (i.e., extreme population differentiation, Fst), rapid evolution since divergence from Neanderthal (i.e., Neanderthal depletion score, NDS), ancient polygenic selection (i.e., Qx scores), and very recent polygenic selection within the past 2,000 years (i.e., trait singleton density scores, tSDS). Variants associated with schizophrenia (Qx = 208.36, p

Congenital inner ear malformations affecting both the osseous and membranous labyrinth can have a devastating impact on hearing and language development. With the exception of an enlarged vestibular aqueduct, non-syndromic inner ear malformations are rare, and their underlying molecular biology has thus far remained understudied. To identify molecular factors that might be important in the developing inner ear, we adopted a family-based trio exome sequencing approach in young unrelated subjects with severe inner ear malformations. We identified two previously unreported de novo loss-of-function variants in GREB1L [c.4368G>T;p.(Glu1410fs) and c.982C>T;p.(Arg328*)] in two affected subjects with absent cochleae and eighth cranial nerve malformations. The cochlear aplasia in these affected subjects suggests that a developmental arrest or problem at a very early stage of inner ear development exists, e.g., during the otic pit formation. Craniofacial Greb1l RNA expression peaks in m...

Disrupted in schizophrenia 1 (DISC1) has been implicated in a number of psychiatric diseases along with neurodevelopmental phenotypes such as the proliferation and differentiation of neural progenitor cells. While there has been significant effort directed toward understanding the function of DISC1 through the determination of its protein-protein interactions within an in vitro setting, endogenous interactions involving DISC1 within a cell type-specific setting relevant to neural development remain unclear. Using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) genome engineering technology, we inserted an endogenous 3X-FLAG tag at the C-terminus of the canonical DISC1 gene in human induced pluripotent stem cells (iPSCs). We further differentiated these cells and used affinity purification to determine protein-protein interactions involving DISC1 in iPSC-derived neural progenitor cells and astrocytes. We were able to determine 151 n...

Many studies have identified changes in the brain associated with obsessive-compulsive disorder (OCD), but few have examined the relationship between genetic determinants of OCD and brain variation.AimsWe present the first genome-wide investigation of overlapping genetic risk for OCD and genetic influences on subcortical brain structures. Using single nucleotide polymorphism effect concordance analysis, we measured genetic overlap between the first genome-wide association study (GWAS) of OCD (1465 participants with OCD, 5557 controls) and recent GWASs of eight subcortical brain volumes (13 171 participants). We found evidence of significant positive concordance between OCD risk variants and variants associated with greater nucleus accumbens and putamen volumes. When conditioning OCD risk variants on brain volume, variants influencing putamen, amygdala and thalamus volumes were associated with risk for OCD. These results are consistent with current OCD neurocircuitry models. Further ...

Clinicians have long considered doubt to be a fundamental characteristic of obsessive-compulsive disorder (OCD). However, the clinical relevance of doubt in OCD has not been addressed. Participants included 1182 adults with OCD who had participated in family and genetic studies of OCD. We used a clinical measure of the severity of doubt, categorized as none, mild, moderate, severe, or extreme. We evaluated the relationship between doubt and OCD clinical features, Axis I disorders, personality and personality disorder dimensions, impairment, and treatment response. The severity of doubt was inversely related to the age at onset of OCD symptoms. Doubt was strongly related to the number of checking symptoms and, to a lesser extent, to the numbers of contamination/cleaning and hoarding symptoms. Doubt also was related to the lifetime prevalence of recurrent major depression and generalized anxiety disorder; to the numbers of avoidant, dependent, and obsessive-compulsive personality disorder traits; and to neuroticism and introversion. Moreover, doubt was strongly associated with global impairment and poor response to cognitive behavioral treatment (CBT), even adjusting for OCD severity and other correlates of doubt. Doubt is associated with important clinical features of OCD, including impairment and cognitive-behavioral treatment response.

Hoarding is common among youth with obsessive compulsive disorder (OCD), with up to 26% of OCD youth exhibiting hoarding symptoms. Recent evidence from adult hoarding and OCD cohorts suggests that hoarding symptoms are associated with executive functioning deficits similar to those observed in subjects with attention deficit hyperactivity disorder (ADHD). However, while hoarding behavior often onsets during childhood, there is little information about executive function deficits and ADHD in affected children and adolescents. The study sample included 431 youths (ages 6-17 years) diagnosed with OCD who participated in the OCD Collaborative Genetics Study and the OCD Collaborative Genetics Association Study and completed a series of clinician-administered and parent report assessments, including diagnostic interviews and measures of executive functioning (Behavior Rating Inventory of Executive Functioning; BRIEF) and hoarding severity (Hoarding Rating Scale-Interview; HRS-I). 113 yout...

Disorders of the brain exhibit considerable epidemiological comorbidity and frequently share symptoms, provoking debate about the extent of their etiologic overlap. We quantified the genetic sharing of 25 brain disorders based on summary statistics from genome-wide association studies of 215,683 patients and 657,164 controls, and their relationship to 17 phenotypes from 1,191,588 individuals. Psychiatric disorders show substantial sharing of common variant risk, while neurological disorders appear more distinct from one another. We observe limited evidence of sharing between neurological and psychiatric disorders, but do identify robust sharing between disorders and several cognitive measures, as well as disorders and personality types. We also performed extensive simulations to explore how power, diagnostic misclassification and phenotypic heterogeneity affect genetic correlations. These results highlight the importance of common genetic variation as a source of risk for brain diso...

Siberia and Western Russia are home to over 40 culturally and linguistically diverse indigenous ethnic groups. Yet, genetic variation of peoples from this region is largely uncharacterized. We present whole-genome sequencing data from 28 individuals belonging to 14 distinct indigenous populations from that region. We combine these datasets with additional 32 modern-day and 15 ancient human genomes to build and compare autosomal, Y-DNA and mtDNA trees. Our results provide new links between modern and ancient inhabitants of Eurasia. Siberians share 38% of ancestry with descendants of the 45,000-year-old Ust-Ishim people, who were previously believed to have no modern-day descendants. Western Siberians trace 57% of their ancestry to the Ancient North Eurasians, represented by the 24,000-year-old Siberian Malta boy. In addition, Siberians admixtures are present in lineages represented by Eastern European hunter-gatherers from Samara, Karelia, Hungary and Sweden (from 8,000-6,600 years a...

RE1-Silencing Transcription factor (REST) has a well-established role in regulating transcription of genes important for neuronal development. Its role in cancer, though significant, is less well understood. We show that REST downregulation in weakly invasive MCF-7 breast cancer cells converts them to a more invasive phenotype, while REST overexpression in highly invasive MDA-MB-231 cells suppresses invasiveness. Surprisingly, the mechanism responsible for these phenotypic changes does not depend directly on the transcriptional function of REST protein. Instead, it is driven by previously unstudied mid-size (30-200 nt) non-coding RNAs (ncRNAs) derived from the first exon of an alternatively spliced REST transcript: REST-003. We show that processing of REST-003 into ncRNAs is controlled by an uncharacterized serine/arginine repeat-related protein, SRRM3. SRRM3 expression may be under REST-mediated transcriptional control, as it increases following REST downregulation. The SRRM3-depen...

Obsessive-compulsive disorder (OCD) is a complex, multifactorial disorder with onset either in childhood or early adulthood. Lifetime prevalence has been estimated to be as high as 3%. Data from twin and family studies, animal models, and genome-wide linkage and association studies have demonstrated a strong genetic component to OCD, as well as overlaps between OCD and body dysmorphic disorder, trichotillomania (hair-pulling disorder), hoarding disorder, and excoriation (skin-picking disorder). Collectively, these disorders are grouped together as OCD-related disorders in DSM-5. In addition, DSM-5 also includes a “tic-related” specifier, recognizing that OCD and Tourette’s syndrome/chronic tics are frequently comorbid. This article summarizes recent findings on the genetics of OCD-related disorders.

To characterize the disease expression of an autosomal recessive human retinal degeneration associated with a mutation in TULP1 (tubby-like protein 1), a gene with currently unknown function. Homozygotes and heterozygotes from an extended Dominican kindred with a TULP1 splice-site gene mutation (IVS14+1,G-->A) were studied clinically and with visual function tests. Sequence analysis of TULP1 was also performed in unrelated patients with severe retinal degeneration from a North American clinic population. Homozygotes had nystagmus, visual acuity of 20/200 or worse, color vision disturbances, bull's eye maculopathy, and peripheral pigmentary retinopathy. Younger patients had a relatively wide extent of kinetic visual fields; older patients had only peripheral islands. No rod function was measurable by psychophysics in any of the patients; markedly reduced cone function was detectable across the visual field of younger patients and in the remaining peripheral islands of older pa...

In an unprecedented finding, Davis et al. [Davis, R. E., Miller, S., Herrnstadt, C., Ghosh, S. S., Fahy, E., Shinobu, L. A., Galasko, D., Thal, L. J., Beal, M. F., Howell, N. & Parker, W. D., Jr. (1997) Proc. Natl. Acad. Sci. USA 94, 4526–4531] used an unusual DNA isolation method to show that healthy adults harbor a specific population of mutated mitochondrial cytochrome c oxidase ( COX ) genes that coexist with normal mtDNAs. They reported that this heteroplasmic population was present at a level of 10–15% in the blood of normal individuals and at a significantly higher level (20–30%) in patients with sporadic Alzheimer’s disease. We provide compelling evidence that the DNA isolation method employed resulted in the coamplification of authentic mtDNA-encoded COX genes together with highly similar COX -like sequences embedded in nuclear DNA (“mtDNA pseudogenes”). We conclude that the observed heteroplasmy is an artifact.

There is increasing evidence that the aetiology of obsessive-compulsive disorder (OCD) has a marked genetic component, although the precise mechanism of inheritance is unclear. Clinical and pharmacological studies have implicated the serotonergic and dopaminergic systems in disease pathogenesis. This study investigated the role of attractive candidate genes in the serotonergic and dopaminergic pathways in the development of OCD. The distribution of selected polymorphic variants in the serotonin receptor type 2A and 1Dbeta (5-HT(2A), 5-HT(1Dbeta)), dopamine transporter (DAT), dopamine receptor type 4 (DRD4) and monoamine-oxidase A (MAO-A) genes were analysed in 71 OCD cases and 129 control individuals in the genetically homogeneous Afrikaner population, by means of case-control association studies. Although no statistically significant genotypic or allelic associations were detected, the data yielded interesting preliminary results that warrant further discussion and investigation.

A history of separation anxiety disorder (SAD) is frequently reported by patients with obsessive-compulsive disorder (OCD). The purpose of this study was to determine if there are clinical differences between OCD-affected individuals with, versus without, a history of SAD. Using data collected during the OCD Collaborative Genetic Study, we studied 470 adult OCD participants; 80 had a history of SAD, whereas 390 did not. These two groups were compared as to onset and severity of OCD, lifetime prevalence of Axis I disorders, and number of personality disorder traits. OCD participants with a history of SAD were significantly younger than the non-SAD group (mean, 34.2 versus 42.2 years; P<.001). They had an earlier age of onset of OCD symptoms (mean, 8.0 versus 10.5 years; P<.003) and more severe OCD, as measured by the Yale-Brown Obsessive Compulsive Scale (mean, 27.5 versus 25.0; P<.005). In addition, those with a history of SAD had a significantly greater lifetime prevalence of agoraphobia (odds ratio (OR) = 2.52, 95% confidence interval (CI) = 1.4-4.6,…

Panic disorder (PD) is a common illness with a definite but "complex" genetic contribution and estimated heritability of 30-46%. We report a genome scan in 120 multiplex PD pedigrees consisting of 1591 individuals of whom 992 were genotyped with 371 markers at an average spacing of 9cM. Parametric two-point, multipoint, and nonparametric analyses were performed using three PD models (Broad, Intermediate, Narrow) and allowing for homogeneity or heterogeneity. The two-point analyses were also performed allowing for independent male and female recombination fractions (theta). Genome-wide significance was empirically evaluated using simulations of this dataset. Evidence for linkage reached genome-wide significance in one region on chromosome 15q (near GABA-A receptor subunit genes) and was suggestive at loci on 2p, 2q and 9p using an averaged theta. Analyses allowing for sex-specific theta's were consistent except that support at one locus on 2q increased to genome-wide significance and an additional region of suggestive linkage on 12q was identified. However, differences in male and female recombination fractions predicted by the sex-specific approach were not consistent with current physical maps. These data provide evidence for chromosomal regions on 15q and 2q that may be important in genetic susceptibility to panic disorder. Although we are encouraged by the findings of analyses using sex-specific recombination fractions, we also note that further understanding of this analytic strategy will be important.

Familial primary pulmonary hypertension (PPH) is a rare autosomal dominant disease characterized by distinctive changes in pulmonary arterioles that lead to increased pulmonary artery pressures, right ventricular failure, and death. Our previous studies had mapped the disease locus, PPH1, to a 27-cM region on chromosome 2q31-q33, with a maximum multipoint logarithm of the odds favoring genetic linkage score of 3.87 with markers D2S350 and D2S364. To narrow the minimal genetic region for PPH, we physically mapped 33 highly polymorphic microsatellite markers and used them to genotype 44 affected individuals and 133 unaffected individuals from 17 families with PPH. We observed recombination events that substantially reduced the interval for PPH1 to the approximately 3-cM region that separates D2S311 and D2S1384. This entire region lies within chromosome 2q33. A maximum two-point lod score of 7.23 at a recombination fraction of zero was obtained for marker D2S307. A maximum multipoint lod score of 7.41 was observed close to marker D2S1367. The current minimal genetic region contains multiple candidate genes for PPH, including a locus thought to play a role in lung cancer.

Family studies have suggested that postpartum mood symptoms might have a partly genetic etiology. The authors used a genome-wide linkage analysis to search for chromosomal regions that harbor genetic variants conferring susceptibility for such symptoms. The authors then fine-mapped their best linkage regions, assessing single nucleotide polymorphisms (SNPs) for genetic association with postpartum symptoms. Subjects were ascertained from two studies: the NIMH Genetics Initiative Bipolar Disorder project and the Genetics of Recurrent Early-Onset Depression. Subjects included women with a history of pregnancy, any mood disorder, and information about postpartum symptoms. In the linkage study, 1,210 women met criteria (23% with postpartum symptoms), and 417 microsatellite markers were analyzed in multipoint allele sharing analyses. For the association study, 759 women met criteria (25% with postpartum symptoms), and 16,916 SNPs in the regions of the best linkage peaks were assessed for association with postpartum symptoms. The maximum linkage peak for postpartum symptoms occurred on chromosome 1q21.3-q32.1, with a chromosome-wide significant likelihood ratio Z score (Z(LR)) of 2.93 (permutation p=0.02). This was a significant increase over the baseline Z(LR) of 0.32 observed at this locus among all women with a mood disorder (permutation p=0.004). Suggestive linkage was also found on 9p24.3-p22.3 (Z(LR)=2.91). In the fine-mapping study, the strongest implicated gene was HMCN1 (nominal p=0.00017), containing four estrogen receptor binding sites, although this was not region-wide significant. This is the first study to examine the genetic etiology of postpartum mood symptoms using genome-wide data. The results suggest that genetic variations on chromosomes 1q21.3-q32.1 and 9p24.3-p22.3 may increase susceptibility to postpartum mood symptoms.