American Journal of Medical Genetics Part B: Neuropsychiatric Genetics最新文献

Genome-wide association studies (GWAS) have identified multiple genomic regions associated with schizophrenia, although many variants reside in noncoding regions characterized by high linkage disequilibrium (LD) making the elucidation of molecular mechanisms challenging. A genomic region on chromosome 10q24 has been consistently associated with schizophrenia with risk attributed to the AS3MT gene. Although AS3MT is hypothesized to play a role in neuronal development and differentiation, work to fully understand the function of this gene has been limited. In this study we explored the function of AS3MT using a neuronal cell line (SH-SY5Y). We confirm previous findings of isoform specific expression of AS3MT during SH-SY5Y differentiation toward neuronal fates. Using CRISPR-Cas9 gene editing we generated AS3MT knockout SH-SY5Y cell lines and used RNA-seq to identify significant changes in gene expression in pathways associated with neuronal development, inflammation, extracellular matrix formation, and RNA processing, including dysregulation of other genes strongly implicated in schizophrenia. We did not observe any morphological changes in cell size and neurite length following neuronal differentiation and MAP2 immunocytochemistry. These results provide novel insights into the potential role of AS3MT in brain development and identify pathways through which genetic variation in this region may confer risk for schizophrenia.

In his 1873 monograph “La Folie Héréditaire,” the French Alienist Legrand du Saulle (LdS) first outlined his understanding of hereditary factors in insanity and then described in detail the theory of Hereditary Madness (HM) that emerged from the writings of his mentor Bénédict Morel. This form of insanity was thought to arise only in families with neuropathic traits. Degeneration theory, proposed by Morel, postulated a within-family “evolution” of increasingly severe psychopathology, typically beginning with mild neuropathic traits and associated idiosyncrasies, and progressing over generations to hereditary madness, mental retardation, epilepsy, and eventual sterility. LdS took strong positions in favor of (i) the heterogeneous transmission of mental illness within families, (ii) consideration of both direct and collateral relatives, and (iii) the inheritance of a predisposition to illness, not the illness itself. He carefully examined the wide range of psychopathology and physical stigmata that occurred in what he called “inheritors” of the neuropathic trait. A unique feature of his work was the use of familial patterns of psychopathology to define a psychiatric disorder. While the theory of HM did not gain wide popularity outside of 19th century France, the concept of neuropathic traits was used extensively in early 20th century psychiatric genetics.

Depressive disorder (DD) is associated with N6-methyladenosine (m6A) hypermethylation. This study sought to explore the molecular mechanism of Methyltransferase-like 3 (METTL3) in cognitive deficits of chronic unpredictable mild stress (CUMS)-treated rats and provide novel targets for DD treatment. A DD rat model was established via CUMS treatment. Cognitive deficits were assessed via body weighing and behavioral tests. METTL3, microRNA (miR)-221-3p, pri-miR-221, GRB2-associated binding protein 1 (Gab1) expressions in hippocampal tissues were detected via RT-qPCR and Western blotting. m6A, DiGeorge syndrome critical region gene 8 (DGCR8)-bound pri-miR-221 and pri-miR-221 m6A levels were measured. The binding relationship between miR-221-3p and Gab1 was testified by dual-luciferase and RNA pull-down assays. Rescue experiments were designed to confirm the role of miR-221-3p and Gab1. METTL3 was highly expressed in CUMS rats, and silencing METTL3 attenuated cognitive deficits of CUMS rats. METTL3-mediated m6A modification facilitated processing and maturation of pri-miR-221 via DGCR8 to upregulate miR-221-3p. miR-221-3p targeted Gab1. miR-221-3p overexpression or Gab1 downregulation reversed the role of silencing METTL3 in CUMS rats. Overall, METTL3-mediated m6A modification facilitated processing and maturation of pri-miR-221 to upregulate miR-221-3p and then inhibit Gab1, thereby aggravating cognitive deficits of CUMS rats.

The presented article is relevant, as the main goals of schizophrenia treatment are to achieve a response to psychopharmacotherapy, reduction and stabilization of psychopathological symptoms, qualitative remission, which in general implies the creation of a stable quality of life for the patient. The purpose of the study was to evaluate the population features of the frequency distribution of alleles and genotypes of polymorphic genetic variants of according to genome-wide association studies analysis of pharmacokinetics-associated antipsychotic medications, in an ethnically homogeneous Kazakh population. The research material was deoxyribonucleic acid (DNA) isolated from the peripheral blood of 1,800 conditionally healthy persons of Kazakh nationality. DNA isolation was carried out by the magnetic polyvinyl alcohol magnetic particle separation method. The analysis of the frequency distribution of the studied genotypes in the Kazakh population showed their compliance with the Hardy–Weinberg equilibrium for all studied polymorphisms (p > .05). The obtained results showed that CYP2C19 (rs4244285, rs4986893) polymorphisms occurs in Kazakhs significantly more often than European and a number of Asian populations, which significantly affects the decrease in effectiveness and increases the risk of side complications during therapy with antipsychotic medications in the Kazakh population.

Suicide accounts for >800,000 deaths annually worldwide; prevention is an urgent public health issue. Identification of risk factors remains challenging due to complexity and heterogeneity. The study of suicide deaths with increased extended familial risk provides an avenue to reduce etiological heterogeneity and explore traits associated with increased genetic liability. Using extensive genealogical records, we identified high-risk families where distant relatedness of suicides implicates genetic risk. We compared phenotypic and polygenic risk score (PRS) data between suicides in high-risk extended families (high familial risk (HFR), n = 1,634), suicides linked to genealogical data not in any high-risk families (low familial risk (LFR), n = 147), and suicides not linked to genealogical data with unknown familial risk (UFR, n = 1,865). HFR suicides were associated with lower age at death (mean = 39.34 years), more suicide attempts, and more PTSD and trauma diagnoses. For PRS tests, we included only suicides with >90% European ancestry and adjusted for residual ancestry effects. HFR suicides showed markedly higher PRS of suicide death (calculated using cross-validation), supporting specific elevation of genetic risk of suicide in this subgroup, and also showed increased PRS of PTSD, suicide attempt, and risk taking. LFR suicides were substantially older at death (mean = 49.10 years), had fewer psychiatric diagnoses of depression and pain, and significantly lower PRS of depression. Results suggest extended familiality and trauma/PTSD may provide specificity in identifying individuals at genetic risk for suicide death, especially among younger ages, and that LFR of suicide warrants further study regarding the contribution of demographic and medical risks.

Suicide is the second cause of death among youths. Genetics may contribute to suicidal phenotypes and their co-occurrence in other neuropsychiatric and medical conditions. Our study aimed to investigate the association of polygenic risk scores (PRSs) for 24 neuropsychiatric, inflammatory, and cardio-metabolic traits/diseases with suicide attempt (SA) or treatment-worsening/emergent suicidal ideation (TWESI). PRSs were computed based on summary statistics of genome-wide association studies. Regression analyses were performed between PRSs and SA or TWESI in four clinical cohorts. Results were then meta-analyzed across samples, including a total of 688 patients with SA (N_eff = 2,258) and 214 with TWESI (N_eff = 785). Stratified genetic covariance analyses were performed to investigate functionally cross-phenotype PRS associations. After Bonferroni correction, PRS for major depressive disorder (MDD) was associated with SA (OR = 1.24; 95% CI = 1.11–1.38; p = 1.73 × 10⁻⁴). Nominal associations were shown between PRSs for coronary artery disease (CAD) (p = 4.6 × 10⁻³), loneliness (p = .009), or chronic pain (p = .016) and SA, PRSs for MDD or CAD and TWESI (p = .043 and p = .032, respectively). Genetic covariance between MDD and SA was shown in 86 gene sets related to drugs having antisuicidal effects. A higher genetic liability for MDD may underlie a higher SA risk. Further, but milder, possible modulatory factors are genetic risk for loneliness and CAD.

Genetic counseling is the process of supporting patients’ and families’ adaptation to genetic information. Psychiatric genetic counseling has been proven to be effective in improving empowerment, self-efficacy, and knowledge even in the absence of genetic testing. Despite this, only one specialist psychiatric genetic counseling clinic currently exists. In order to engage genetic counselors in providing psychiatric genetic counseling, a 2-day workshop: “Psychiatric Genetic Counseling for Genetic Counselors”, was developed and implemented aimed at empowering genetic counselors to feel confident and competent in this practice domain. The aim of the study was to qualitatively explore the impact of the workshop. Semistructured interviews were carried out with 12 genetic counselors who attended the workshop between 2015 and 2018. Thematic analysis revealed that the workshop empowered all participants to feel comfortable and confident offering psychiatric genetic counseling to patients. Participants also reflected how the workshop highlighted the stigma associated with mental illnesses and offered support in normalizing these conditions. Overall, this study presents that the “Psychiatric Genetic Counseling for Genetic Counselors” workshop fulfilled its proposed aims and outcomes.

This essay provides the historical context and key findings of one of the largest fieldwork-based family studies ever done in the history of psychiatric genetics conducted in Berlin by Franz Kallmann from 1929 to 1933. It included over 1,000 schizophrenic probands and 12,500 of their relatives including siblings, offspring, nieces/nephews and grandchildren. The work was analyzed in close collaboration with Rüdin, Schulz, and Luxenburger in Munich. Born of Jewish parents, Kallmann had to leave Germany in 1936, completing and publishing the monograph in the United States in 1938. This study included a number of methodologic advances over the classic 1916 sibling study of Rüdin: (a) joint analysis of multiple classes of relatives; (b) subdivision of schizophrenia into four subtypes; (c) a focus on schizoid personality [schizoidia]; (d) examination of the familial aggregation of schizophrenia; and (e) a more complex genetic model—with schizophrenia arising from a single-recessive gene with 70% penetrance and background polygenic influences, and schizoidia from heterozygotes. Kallmann found important differences in risk of relatives in nuclear versus peripheral subtypes and concluded that schizoidia was a part of schizophrenia disease complex while other psychopathies, feeblemindedness, and organic brain disorders were not. Kallmann was strongly invested in the eugenic implications of his results.