December 2025

Common Genetic Variants in TRIO Are Associated With Autism in Chinese Han Population

Han Shen, Xiaoxuan Sun, Ziqi Wang, Miaomiao Jiang, Jinxin Wang, Tianlan Lu, Weihua Yue, Dai Zhang, Lifang Wang, Jun Li

Autism spectrum disorders (ASDs) are a group of neurodevelopmental disorders with high heritability. Nevertheless, the involvement of genetic variants in ASDs is not fully understood. One gene of interest is TRIO, which encodes a large protein that aids in GDP-to-GTP exchange as a Ras homologous (Rho) guanine nucleotide exchange factor (GEF), facilitating cytoskeleton reorganization. Thus, it plays crucial roles in neuronal migration, neurite outgrowth, and synaptic transmission. De novo mutations in TRIO have been extensively reported in the pathogenesis of ASDs. However, no evidence currently supports the genetic association between common variants in TRIO and ASDs. To investigate the role of common genetic variations in autism risk, we analyzed 12 tagging single-nucleotide polymorphisms (SNPs) in the TRIO gene. These tagging SNPs captured an average of 75% of all common variations in TRIO with a minor allele frequency (MAF) > 5%. Using the family-based association study in 239 Chinese Han autism trios, we identified the significant association of three SNPs (rs32593, rs33005, and rs27479) with autism. To confirm the association, the sample size was expanded to 427 trios by recruiting 188 additional trios. Our findings across all 427 trios confirmed that A allele of rs32593, G allele of rs33005, and C allele of rs27479 showed a preferential transmission to the affected offspring (rs32593: A > G, Z = 2.600, p = 0.0093; rs33005: G > T, Z = 2.978, p = 0.0029; rs27479: C > A, Z = 3.214, p = 0.0013) after Bonferroni’s correction (p < 0.0042). Haplotype analyses showed that one haplotype (A-G) constructed from rs32593 and rs33005 was significantly associated with autism (p = 0.0064; Global p = 0.022). These results suggested that the common variants in TRIO might be involved in the susceptibility to autism in the Chinese Han population.

Correction: Deficiency of autism susceptibility gene Trio in cerebellar Purkinje cells leads to delayed motor impairments

november 2025

Antipsychotic Use Among Intellectually Disabled Individuals With Rare Genetic Variants That Confer Risk for Schizophrenia

Mark Ainsley Colijn

While this study had numerous limitations that prevent firm conclusions from being drawn, it provides preliminary evidence that antipsychotics may be relatively safe and effective in at least some of the genetic disorders most strongly associated with schizophrenia.

September 2025

1 Mb Deletion in 10q26.3 and the Likely Pathogenic Variant in the TRIO Gene: A Twin Case Study Challenging Their Role in Autism Diagnosis

Silvia Lakatosova

Here, we present a case study of twin boys aged 2 and 7 years who both met the diagnostic criteria for autism spectrum disorders (ASDs) based on the standard diagnostic instruments ADOS‐2 and ADI‐R. The clinical indication for genetic diagnostics in the first boy was autism with high severity of symptoms, delayed speech development, and mild facial dysmorphia. The second boy’s indication was autism with moderate severity of symptoms, delayed speech development, mild facial features, slowed psychomotor development, and microcephaly. The microarray‐based analysis of chromosome aberrations revealed a heterozygous 977,456 bp deletion of region 10q26.3 in both boys. The region includes 28 genes, some of these genes are important in the development of the central nervous and urogenital systems, and heterozygous deletions in this region have been associated with mental retardation, growth and development disorders, and craniofacial anomalies. The whole exome sequencing confirmed the presence of this deletion in both boys and, at the same time, led to the identification of a pathogenic SNV variant in the TRIO gene in the boy with microcephaly and delayed psychomotor development, which may explain the different phenotype of both boys. However, the segregation analysis of these variants in the family revealed that the microdeletion was inherited from the asymptomatic father, and the c.2149C > T variant in the TRIO gene was inherited from the asymptomatic mother, making the diagnostic finding uncertain. This case highlights that when pathogenic or likely pathogenic variants are inherited from unaffected parents, the clinical phenotype may result from a combined burden of multiple rare variants and polygenic risk, underscoring the importance of a comprehensive genomic analysis in complex cases. Thus, we emphasize the importance of utilizing available methods, such as whole exome sequencing besides microarray‐based comparative genomic hybridization, in the genetic diagnosis of autism patients in Slovakia.

June 2025

Neurodevelopmental Disorders: Unraveling the impact of genetic variants

Bruce Herring

Neurodevelopmental disorders like autism spectrum disorder, schizophrenia, and bipolar disorder are deeply complex conditions, with each involving a mosaic of genetic and environmental contributors. A number of risk genes have been identified, but pinpointing how a particular mutation in one of these genes translates into specific neuronal and behavioral phenotypes remains a challenge.

MAY 2025

YAP controls cell migration and invasion through a Rho GTPase switch

Sagar R. Shah, Chunxiao Ren, Nathaniel D. Tippens, JinSeok Park, Ahmed Mohyeldin, Shuyan Wang, Guillermo Vela, Juan C. Martinez-Gutierrez, Seth S. Margolis, Susanne Schmidt, Alfredo Quiñones-Hinojosa, and Andre Levchenko

Delineating the mechanisms that control the movement of cells is central to understanding diverse physiological and pathophysiological processes. The transcriptional coactivator YAP is important during development and associated with cancer metastasis. Here, we found that YAP promoted cell migration by modulating a Rho family guanosine triphosphatase (GTPase) switch involving Rac1 and RhoA, which are key regulators of cytoskeletal dynamics. YAP transcriptionally transactivated the gene encoding the Rac1 guanine nucleotide exchange factor TRIO by directly binding to its intronic enhancer. This led to the activation of Rac1 and inhibition of RhoA, which increased cell migration and invasion in vitro and in vivo. This YAP-dependent program was observed across many cell types, including human breast epithelial cells and astrocytes, but it was particularly enhanced in a patient-specific manner in glioblastoma (GBM), the most common malignant brain tumor. Additionally, YAP-TRIO signaling activated STAT3, a transcription factor implicated in invasive growth in cancer, suggesting potential for cross-talk with this pathway to exacerbate invasive behavior. Clinically, hyperactivation of YAP, TRIO, and STAT3 gene signatures in GBM were associated with poor survival outcomes in patients. Our findings suggest that the YAP-TRIO-Rho-GTPase signaling network regulates invasive cell spread in both physiological and pathological contexts.

Heterozygosity for neurodevelopmental disorder-associated TRIO variants yields distinct deficits in behavior, neuronal development, and synaptic transmission in mice

Yevheniia Ishchenko, Amanda T Jeng, Shufang Feng, Timothy Notto, li Cindy Manriquez-Rodriguez, Khanh K Nguyen, Melissa G Carrizales, Matthew J Vitarelli, Ellen E Corcoran, Anthony J Koleske

Genetic variants in TRIO are associated with neurodevelopmental disorders (NDDs) including schizophrenia (SCZ), autism spectrum disorder (ASD) and intellectual disability. TRIO uses its two guanine nucleotide exchange factor (GEF) domains to activate GTPases (GEF1: Rac1 and RhoG; GEF2: RhoA) that control neuronal development and connectivity. It remains unclear how discrete TRIO variants differentially impact these neurodevelopmental events. Here, we investigate how heterozygosity for NDD-associated Trio variants – +/K1431M (ASD), +/K1918X (SCZ), and +/M2145T (bipolar disorder, BPD) – impact mouse behavior, brain development, and synapse structure and function. Heterozygosity for different Trio variants impacts motor, social, and cognitive behaviors in distinct ways that model clinical phenotypes in humans. Trio variants differentially impact head and brain size, with corresponding changes in dendritic arbors of motor cortex layer 5 pyramidal neurons (M1 L5 PNs). Although neuronal structure was only modestly altered in the Trio variant heterozygotes, we observe significant changes in synaptic function and plasticity. We also identified distinct changes in glutamate synaptic release in +/K1431M and +/M2145T cortico-cortical synapses. The TRIO K1431M GEF1 domain has impaired ability to promote GTP exchange on Rac1, but +/K1431M mice exhibit increased Rac1 activity, associated with increased levels of the Rac1 GEF Tiam1. Acute Rac1 inhibition with NSC23766 rescued glutamate release deficits in +/K1431M variant cortex. Our work reveals that discrete NDD-associated Trio variants yield overlapping but distinct phenotypes in mice, demonstrates an essential role for Trio in presynaptic glutamate release, and underscores the importance of studying the impact of variant heterozygosity in vivo.

The Rho GEF Trio functions in contact inhibition of locomotion of neural crest cells by interacting with Ptk7

Katharina Till, Annette Borchers

Neural crest (NC) cells are highly migratory cells that contribute to a wide range of vertebrate tissues and must respond to a variety of external signals to precisely control directed cell migration. The RhoGEF Trio is particularly well suited to relay signals to the cytoskeleton because it contains two GEF domains that activate Rac1 and RhoA, respectively. Previously, we have shown that Trio is dynamically localized in Xenopus NC cells and required for their migration. However, how its distinct enzymatic functions are spatially controlled remains unclear. Here, we show that Trio is required for contact inhibition of locomotion (CIL), a phenomenon whereby NC cells change their polarity and directionality upon cell-cell contact. At cell-cell contacts, Trio interacts with Ptk7, a regulator of planar cell polarity that we have recently shown to be required for CIL. Our data suggest that Ptk7 inhibits the Rac1 activity of Trio, thereby limiting Trio activity to the activation of RhoA and promoting CIL.

april 2025

Deficiency of autism susceptibility gene Trio in cerebellar Purkinje cells leads to delayed motor impairments

Jinxin Wang, Yimeng Li, Dai Zhang, Wenzhi Sun, Jun Li

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders characterized by social interaction deficits, restricted interests and repetitive behaviors. The co-occurrence of motor impairments exacerbates the severity and societal impact of ASD, but the underlying mechanism remains to be elucidated. Research on the comorbidities of ASD including motor impairments could benefit in the life quality improvement in patients with ASD. Here we aimed at investigating the motor behaviors in mice with Trio deletion in Purkinje cells (PCs), and further exploring the cellular and molecular mechanisms. The protein level of Calbindin as PCs’ marker was determined. Behaviors including spontaneous locomotion activity, rotarod, beam balance and gait were tested in mice with the ages of 12-week and 20-week. Magnetic resonance imaging (MRI) scanning with T2 and DTI sequencing was performed in 12-week old mice. Although Triofl/fl; Pcp2-Cre mice showed significant impairments of spontaneous locomotion activity in both 12-week and 20-week ages, only the 20-week but not 12-week Triofl/fl; Pcp2-Cre mice showed extra mild abnormal motor, fine motor coordination, and gait. The decreased expression of Calbindin existed in both 12-week and 20-week old mice compared with control. Differentially expressed genes analysis from RNA-Seq and Gene Co-expression Network Analysis (GCNA) showed that Syne1 and its co-expressed genes were upregulated in Triofl/fl; Pcp2-Cre mice compared to controls. In addition, abnormal ADC values suggested the long-term chronic damage in the cerebellum. Together, our findings indicate that the motor dysfunction in ASD are affected by Trio deletion in PCs with delayed in onset, accompanied with alterations in MRI, histological, and epigenetic level.

FEBRUARY 2025

Genetic variants and phenotypic data curated for the CAGI6 intellectual disability panel challenge

Maria Cristina Aspromonte, Alessio Del Conte, Roberta Polli, Demetrio Baldo, Francesco Benedicenti, Elisa Bettella, Stefania Bigoni, Stefania Boni, Claudia Ciaccio, Stefano D’Arrigo, Ilaria Donati, Elisa Granocchio, Isabella Mammi, Donatella Milani, Susanna Negrin, Margherita Nosadini, Fiorenza Soli, Franco Stanzial, Licia Turolla, Damiano Piovesan, Silvio C. E. Tosatto, Alessandra Murgia & Emanuela Leonardi

Neurodevelopmental disorders (NDDs) are common conditions including clinically diverse and genetically heterogeneous diseases, such as intellectual disability, autism spectrum disorders, and epilepsy. The intricate genetic underpinnings of NDDs pose a formidable challenge, given their multifaceted genetic architecture and heterogeneous clinical presentations. This work delves into the intricate interplay between genetic variants and phenotypic manifestations in neurodevelopmental disorders, presenting a dataset curated for the Critical Assessment of Genome Interpretation (CAGI6) ID Panel Challenge. The CAGI6 competition serves as a platform for evaluating the efficacy of computational methods in predicting phenotypic outcomes from genetic data. In this study, a targeted gene panel sequencing has been used to investigate the genetic causes of NDDs in a cohort of 415 paediatric patients. We identified 60 pathogenic and 49 likely pathogenic variants in 102 individuals that accounted for 25% of NDD cases in the cohort. The most mutated genes were ANKRD11, MECP2, ARID1B, ASH1L, CHD8, KDM5C, MED12 and PTCHD1 The majority of pathogenic variants were de novo, with some inherited from mildly affected parents. Loss-of-function variants were the most common type of pathogenic variant. In silico analysis tools were used to assess the potential impact of variants on splicing and structural/functional effects of missense variants. The study highlights the challenges in variant interpretation especially in cases with atypical phenotypic manifestations. Overall, this study provides valuable insights into the genetic causes of NDDs and emphasises the importance of understanding the underlying genetic factors for accurate diagnosis, and intervention development in neurodevelopmental conditions.